EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 11 2005
B. Ravindra Babu
Abstract Fully modified homopyrimidine 2'-deoxy- xylo nucleic acid (dXNA) form triple helixes with complementary DNA/RNA with thermal stabilities comparable to those of the corresponding DNA:DNA and DNA:RNA duplexes. However, a single or few insertions of dXNA monomers in a DNA strand significantly lower duplex stabilities. The dXNA monomers are known to adopt predominantly an N -type furanose conformation in solution. With a desire to increase the binding affinity, seven sugar-modified XNA monomers (H, F, N, M, K, P and Q) have been synthesised and their effect on hybridization towards DNA and RNA complements studied. The introduction of 2'-fluoro and 2'-hydroxy substituents was expected to induce conformational restriction towards C3'- endo -type furanose conformation of monomer F derived from 1-(2'-deoxy-2'-fluoro-,- D -xylofuranosyl)thymine and monomer H derived from 1-(,- D -xylofuranosyl)thymine. The presence of functionalites facing the minor groove as in 1-(2'-amino-2'-deoxy-2'- N,4'- C -methylene-,- D -xylofuranosyl)thymine (monomer N), 1-[4- C -(N -methylpiperazinyl)methyl-,- D -xylofuranosyl]thymine (monomer P), 1-(4- C -piperazinylmethyl-,- D -xylofuranosyl)thymine (monomer Q), 1-(4- C -hydroxymethyl-,- D -xylofuranosyl)thymine (monomer M) and 9-(4- C -hydroxymethyl-,- D -xylofuranosyl)adenine (monomer K) was studied, with monomer N being locked in an N -type furanose conformation. Besides, an efficient synthesis of known xylo -LNA phosphoramidite 19, required for the incorporation of 1-(2'- O,4'- C -methylene-,- D -xylofuranosyl)thymine (monomer L) is described. For comparison, hydridization data of various XNAs reported in the literature are included in the discussion section. The thermal denaturation studies show that XNAs containing conformationally locked monomers (N and L) display improved binding affinity, and that partially modified DNA/XNA chimera, or fully modified XNA display preferential hybridization towards RNA complements. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source]

Raman optical activity of an achiral element in a chiral environment

JOURNAL OF RAMAN SPECTROSCOPY, Issue 9 2009
Andrew M. Smith
Abstract Raman optical activity (ROA) is a relatively new technique used to determine the structure of chiral molecules and is proving useful in the study of biological molecules such as proteins and DNA/RNA. Here, for the first time, we demonstrate the applicability of ROA as a technique to study achiral groups in chiral environments, detecting the induced chirality of N -(fluorenyl-9-methoxycarbonyl) (Fmoc) in a chiral self-assembled structure of Fmoc-dipeptides. This technique is therefore of interest to those studying self-assembled systems that adopt a chiral structure. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Photocrosslinked DNA Nanospheres for Drug Delivery

MACROMOLECULAR RAPID COMMUNICATIONS, Issue 13 2010
Young Hoon Roh
Abstract DNA has been employed as both a genetic and a generic material. X-shaped DNA (X-DNA) in particular has four branched arms, providing multivalent functionalities that can allow for simultaneous multiple crosslinking. Here we report the synthesis of four acrylate-functionalized X-DNA monomers that can be further photocrosslinked to form monodisperse and tunable DNA nanospheres. In particular, the size and surface charge of these nanospheres were precisely controlled in a linear fashion, simply by tuning the monomer concentration in the reaction. The morphology and surface properties of the nanospheres were characterized using FT-IR, HPLC, TEM, AFM, zeta potential, and DLS analysis. In vitro studies in mammalian cells revealed that these DNA nanospheres demonstrated significant efficacy in the delivery of doxorubicin. These results highlight the potential of using DNA as material building blocks to design novel nanocarriers with properties tailored for the delivery of drugs in general and DNA/RNA in particular. [source]

Current awareness in prenatal diagnosis

PRENATAL DIAGNOSIS, Issue 9 2009
Article first published online: 28 AUG 200
In order to keep subscribers up-to-date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of prenatal diagnosis. Each bibliography is divided into 21 sections: 1 Reviews; 2 General Interest; 3 Normal Fetal Development; 4 Preimplantation Genetic Diagnosis; 5 First Trimester Diagnosis; 6 Second Trimester Diagnosis; 7 Fetal Imaging: General; Ultrasound; MRI; 8 Maternal Serum Screening for Aneuploidy; 9 Screening for Carriers of Genetic Abnormality; 10 Molecular Cytogenetics: Metaphase Cytogenetics/FISH; Array CGH; 11 Fetal Cells in Maternal Circulation; 12 Fetal DNA/RNA in Maternal Body Fluids; 13 Fetal Therapy; 14 Psychosocial and Ethical Aspects; 15 Epidemiology and Environmental Factors; 16 Developmental and Placental Pathology; 17 Genetic Counseling. Within each section, articles are listed in alphabetical order with respect to author. If, in the preceding period, no publications are located relevant to any one of these headings, that section will be omitted [source]

Current awareness in prenatal diagnosis

PRENATAL DIAGNOSIS, Issue 4 2009
Article first published online: 30 MAR 200
In order to keep subscribers up-to-date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of prenatal diagnosis. Each bibliography is divided into 20 sections: 1 Reviews; 2 General Interest; 3 Normal Fetal Development; 4 Preimplantation Genetic Diagnosis; 5 First Trimester Diagnosis; 6 Second Trimester Diagnosis; 7 Fetal Imaging: General; Ultrasound; MRI; 8 Maternal Serum Screening for Aneuploidy; 9 Screening for Carriers of Genetic Abnormality; 10 Molecular Cytogenetics: Metaphase Cytogenetics/FISH; Array cGH; 11 Fetal Cells in Maternal Circulation; 12 Fetal DNA/RNA in Maternal Body Fluids; 13 Fetal Therapy; 14 Psychosocial and Ethical Aspects; 15 Epidemiology and Environmental Factors; 16 Developmental and Placental Pathology; 17 Genetic Counseling. Within each section, articles are listed in alphabetical order with respect to author. If, in the preceding period, no publications are located relevant to any one of these headings, that section will be omitted [source]

Current awareness in prenatal diagnosis

PRENATAL DIAGNOSIS, Issue 3 2009
Article first published online: 26 FEB 200
In order to keep subscribers up-to-date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of prenatal diagnosis. Each bibliography is divided into 20 sections: 1 Reviews; 2 General Interest; 3 Normal Fetal Development; 4 Preimplantation Genetic Diagnosis; 5 First Trimester Diagnosis; 6 Second Trimester Diagnosis; 7 Fetal Imaging: General; Ultrasound; MRI; 8 Maternal Serum Screening for Aneuploidy; 9 Screening for Carriers of Genetic Abnormality; 10 Molecular Cytogenetics: Metaphase Cytogenetics/FISH; Array cGH; 11 Fetal Cells in Maternal Circulation; 12 Fetal DNA/RNA in Maternal Body Fluids; 13 Fetal Therapy; 14 Psychosocial and Ethical Aspects; 15 Epidemiology and Environmental Factors; 16 Developmental and Placental Pathology; 17 Genetic Counseling. Within each section, articles are listed in alphabetical order with respect to author. If, in the preceding period, no publications are located relevant to any one of these headings, that section will be omitted [source]

Heating-induced conformational change of a novel ,-(1,3)- D -glucan from Pleurotus geestanus

BIOPOLYMERS, Issue 2 2010
Mei Zhang
Abstract Recently, we isolated and purified a neutral polysaccharide (PGN) from edible fungus Pleurotus geestanus. Its structure was characterized by a range of physical,chemical methods, including high performance anion exchange chromatography, uronic acid, and protein analyses, size exclusion chromatography with ultraviolet, refractive index and light scattering detectors, and nuclear magnetic resonance. Our results revealed that PGN is a novel ,-(1,3)- D -glucan with glucose attached to every other sugar residues at Position 6 in the backbone. It has a degree of branching of 1/2. Such structure is different from typical ,-(1,3)- D -glucans schizophyllan and lentinan in which DB is 1/3 and 2/5, respectively. Rheological study showed a very interesting melting behavior of PGN in water solution: heating PGN in water leads to two transitions, in the range of 8,12.5°C and 25,60°C, respectively. The melting behavior and conformational changes were characterized by rheometry, micro-differential scan calorimetry, atomic force microscopy, static and dynamic light scattering at different temperatures. The first heating-induced transition corresponds to the disintegration of polymer bundles into small helical clusters, resembling the heating-induced dissociation of SPG in water at 7°C; the second one might correspond to the dissociation of helical strands to individual chains. The ability of PGN to undergo a conformation/viscosity transition in water upon heating is very valuable to immobilize cells or enzymes or therapeutic DNA/RNA, which makes PGN a potentially useful biomaterial. © 2009 Wiley Periodicals, Inc. Biopolymers 93: 121,131, 2010. This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com [source]

Viral clearance using disposable systems in monoclonal antibody commercial downstream processing

BIOTECHNOLOGY & BIOENGINEERING, Issue 3 2008
Joe X. Zhou
Abstract Once highly selective protein A affinity is chosen for robust mAb downstream processing, the major role of polishing steps is to remove product related impurities, trace amounts of host cell proteins, DNA/RNA, and potential viral contaminants. Disposable systems can act as powerful options either to replace or in addition to polishing column chromatography to ensure product purity and excellent viral clearance power for patients' safety. In this presentation, the implementation of three disposable systems such as depth filtration, membrane chromatography, and nanometer filtration technology in a commercial process are introduced. The data set of viral clearance with these systems is presented. Application advantages and disadvantages including cost analysis are further discussed. Biotechnol. Bioeng. 2008;100: 488,496. © 2008 Wiley Periodicals, Inc. [source]

Maximum likelihood constrained deconvolution.

CONCEPTS IN MAGNETIC RESONANCE, Issue 2 2003
II: Application to experimental two-, three-dimensional NMR spectra
Abstract The maximum likelihood method (MLM) and related protocols were applied to the experimental 2-D nuclear Overhauser effect (NOE) spectrum of a 24-nucleotide RNA hairpin loop molecule. The output becomes more valuable when diagonal symmeterization is followed by MLM. This symmeterized maximum likelihood (SML) protocol restores the original spectral information with high fidelity by accurately partitioning components from overlapped peaks and provides substantial improvements in line shape and spectral resolution, in particular in the F1 dimension. These advantages lead to a simpler interpretation of the resonance frequencies, intensities, multiplet fine structure, and J -coupling values from a heavily overlapped peak region. This promises a more effective tool for peak picking, assignment, and integration. Also, application of MLM and related protocols to the 2-D NOE proton spectrum of a 24-mer RNA dramatically increases the number of NOE-based distance constraints that can be used for determination of its 3-D molecular structure. By application of 3-D MLM to a simple 3-D spectrum, the spectral resolution and signal-to-noise (S/N) ratio was greatly improved by effective line sharpening and reduction of cross-talk between planes. © 2003 Wiley Periodicals, Inc. Concepts Magn Reson 18A: 146,156, 2003 [source]

TRAF6 knockdown promotes survival and inhibits inflammatory response to lipopolysaccharides in rat primary renal proximal tubule cells

ACTA PHYSIOLOGICA, Issue 3 2010
S. Liu
Abstract Aim:, TRAF6 is a unique adaptor protein of the tumour necrosis factor receptor-associated factor family that mediates both tumour necrosis factor receptor (TNFR) and interleukin-1 receptor/Toll-like receptor (IL-1R/TLR) signalling. Activation of IL-1R/TLR and TNFR pathways in renal tubular cells contributes to renal injury. This study aimed to investigate if blockade of lipopolysaccharide (LPS)-triggered TLR4 signalling by small interfering RNA (siRNA) targeting TRAF6 protects survival and inhibits inflammatory response in isolated rat renal proximal tubular cells (PTCs). Methods:, PTCs isolated from F344 rat kidneys were transfected with chemically synthesized siRNA targeting TRAF6 mRNA. Real-time quantitative PCR was applied to measure mRNA level of TRAF6, TNF-,, IL-6 and monocyte chemoattractant protein-1 (MCP-1). Protein levels of extracellular signal-regulated kinase (ERK), c-jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase, caspase 3 and cleaved caspase 3 were evaluated by Western blotting. Cell viability was analysed with XTT reagents. Results:, We found that the TRAF6 gene was effectively silenced in PTCs using siRNA. TRAF6 knockdown resulted in reduced TNF-, and IL-6 mRNA expression upon LPS challenge. LPS-induced phosphorylation of JNK and p38 was attenuated in TRAF6 siRNA-transfected cells while the change in the phosphorylation of ERK was not remarkable. TRAF6 knockdown was associated with increased cell viability and reduced protein level of cleaved caspase-3, both, in the absence and presence of LPS. Conclusion:, Our studies suggest that TRAF6 knockdown may inhibit inflammatory response and promote cell survival upon LPS challenge in primary rat proximal renal tubular cells. [source]

Effects of short-term food deprivation on orexin-A-induced intestinal bicarbonate secretion in comparison with related secretagogues

ACTA PHYSIOLOGICA, Issue 3 2010
G. Flemström
Abstract Studies of gastrointestinal physiology in humans and intact animals are usually conducted after overnight fast. We compared the effects of orexin-A, vasoactive intestinal polypeptide (VIP), melatonin, serotonin, uroguanylin, ghrelin and prostaglandin E2 (PGE2) on duodenal bicarbonate secretion in fed and overnight fasted animals. This review is a summary of our findings. Secretagogues were administered by intra-arterial infusion or luminally (PGE2). Enterocyte intracellular calcium ([Ca2+]i) signalling was studied by fluorescence imaging. Total RNA was extracted, reverse transcripted to cDNA and expression of orexin receptors measured by quantitative real-time PCR. Orexin-A stimulates the duodenal secretion in continuously fed animals but not in food-deprived animals. Similarly, short-term fasting causes a 100-fold decrease in the amount of the muscarinic agonist bethanechol required for stimulation of secretion. In contrast, fasting does not affect secretory responses to intra-arterial VIP, melatonin, serotonin, uroguanylin and ghrelin, or that to luminal PGE2. Orexin-A induces [Ca2+]i signalling in enterocytes from fed rats but no significant [Ca2+]i responses occur in enterocytes from fasted animals. In addition, overnight fasting decreases the expression of mucosal orexin receptors. Short-term food deprivation thus decreases duodenal expression of orexin receptors and abolishes the secretory response to orexin-A as well as orexin-A-induced [Ca2+]i signalling. Fasting, furthermore, decreases mucosal sensitivity to bethanechol. The absence of declines in secretory responses to other secretagogues tested strongly suggests that short-term fasting does not affect the secretory capacity of the duodenal mucosa in general. Studies of intestinal secretion require particular evaluation with respect to feeding status. [source]

P28 Interleukin-8 from keratinocytes can be used to test for contact allergy

CONTACT DERMATITIS, Issue 3 2004
Bolli Bjarnason
Objective:, To investigate whether secretion of interleukin-8 (IL-8) proteins by keratinocytes following in vitro exposure to a contact allergen can be used to detect contact allergy. Methods:, Suction blisters were made on skin of allergic and anergic subjects to urushiol, the contact allergen of poison ivy. Keratinocyte cultures were prepared and exposed to the allergen in vitro. Controls were the allergen solvent. Variable allergen concentrations, allergen exposure times and cell culture times were used. At the end of each culture time, IL-8 RNA and protein of the culture supernatants were analyzed by PCR and ELISA. Results:, The concentration of IL-8 in the supernatants proved to be a successful way to distinguish between subjects who patch tested positive with a non-toxic concentration of urushiol and subjects who tested negative. In the allergic subjects, a correlation was established between the dose of the allergen and the IL-8 protein concentration in the supernatants. Conclusions:, In vitro testing of contact allergies in patients makes possible an objective assessment of their allergic status without causing a booster effect or risking active sensitizations. The results indicate that the method may be used as an alternative method to animal models for testing consumer products before their marketing, thus avoiding ethical problems and problems related to interpretation of tests because of biological differences between animals and humans. [source]

Myosin Vb localises to nucleoli and associates with the RNA polymerase I transcription complex

CYTOSKELETON, Issue 12 2009
Andrew J. Lindsay
Abstract It is becoming increasingly clear that the mammalian class V myosins are involved in a wide range of cellular processes such as receptor trafficking, mRNA transport, myelination in oligodendrocytes and cell division. Using paralog-specific antibodies, we observed significant nuclear localisation for both myosin Va and myosin Vb. Myosin Vb was present in nucleoli where it co-localises with RNA polymerase I, and newly synthesised ribosomal RNA (rRNA), indicating that it may play a role in transcription. Indeed, its nucleolar pattern was altered upon treatment with RNA polymerase I inhibitors. In contrast, myosin Va is largely excluded from nucleoli and is unaffected by these inhibitors. Myosin Vb was also found to physically associate with RNA polymerase I and actin in co-immunoprecipitation experiments. We propose that myosin Vb serves a role in rRNA transcription. Cell Motil. Cytoskeleton 2009. © 2009 Wiley-Liss, Inc. [source]

A minor ,-tubulin essential for mammalian cell proliferation

CYTOSKELETON, Issue 9 2008
Rajat Bhattacharya
Abstract Mammals use tubulin from multiple genes to construct microtubules. Some genes are expressed in a tissue specific manner, while others are expressed in almost all cell types. ,5-Tubulin is a minor, ubiquitous isoform whose overexpression was recently shown to disrupt microtubules. Using inhibitory RNA, we now report that suppression of ,5 production in both human and hamster cells blocks cell proliferation. Cells depleted of ,5 either trigger the mitotic checkpoint and undergo apoptosis; or they experience a transient mitotic block, a high incidence of lagging chromosomes, and progression into G1 without cytokinesis to become large, flat cells with elevated DNA content. Microtubules appear to be normally organized in cells depleted of ,5, but they are rich in acetylated ,-tubulin indicating that they may be more stable than normal. The results provide the first evidence that a specific isoform of ,-tubulin is required for mitosis. Cell Motil. Cytoskeleton 2008. © 2008 Wiley-Liss, Inc. [source]

Actin stress fiber pre-extension in human aortic endothelial cells

CYTOSKELETON, Issue 4 2008
Lan Lu
Abstract Actin stress fibers (SFs) enable cells to sense and respond to mechanical stimuli and affect adhesion, motility and apoptosis. We and others have demonstrated that cultured human aortic endothelial cells (HAECs) are internally stressed so that SFs are pre-extended beyond their unloaded lengths. The present study explores factors affecting SF pre-extension. In HAECs cultured overnight the baseline pre-extension was 1.10 and independent of the amount of cell shortening. Decreasing contractility with 30 mM BDM or 10 ,M blebbistatin decreased pre-extension to 1.05 whereas increasing contractility with 2 nM calyculin A increased pre-extension to 1.26. Knockdown of ,-actinin-1 with an interfering RNA increased pre-extension to 1.28. None of these affected the wavelength of the buckled SFs. Pre-extension was the same in unperturbed cells as in those in which the actin cytoskeleton was disrupted by both chemical and mechanical means and then allowed to reassemble. Finally, disrupting MTs or IFs did not affect pre-extension but increased the wavelength. Taken together, these results suggest that pre-extension of SFs is determined primarily by intrinsic factors, i.e. the level of actin-myosin interaction. This intrinsic control of pre-extension is sufficiently robust that pre-extension is the same even after the actin cytoskeleton has been disrupted and reorganized. Unlike pre-extension, the morphology of the compressed SFs is partially determined by MTs and IFs which appear to support the SFs along their lengths. Cell Motil. Cytoskeleton 2008. © 2008 Wiley-Liss, Inc. [source]

Evolution and persistence of the cilium

CYTOSKELETON, Issue 12 2007
Peter Satir
Abstract The origin of cilia, a fundamental eukaryotic organelle, not present in prokaryotes, poses many problems, including the origins of motility and sensory function, the origins of nine-fold symmetry, of basal bodies, and of transport and selective mechanisms involved in ciliogenesis. We propose the basis of ciliary origin to be a self-assembly RNA enveloped virus that contains unique tubulin and tektin precursors. The virus becomes the centriole and basal body, which would account for the self-assembly and self-replicative properties of these organelles, in contrast to previous proposals of spirochaete origin or endogenous differentiation, which do not readily account for the centriole or its properties. The viral envelope evolves into a sensory bud. The host cell supplies the transport machinery and molecular motors to construct the axoneme. Polymerization of cytoplasmic microtubules in the 9 + 0 axoneme completes the 9 + 2 pattern. Cell Motil. Cytoskeleton 2007. © 2007 Wiley-Liss, Inc. [source]

Molecular identification and localization of cellular titin, a novel titin isoform in the fibroblast stress fiber

CYTOSKELETON, Issue 6 2007
Peter J. Cavnar
Abstract We previously discovered a large titin-like protein,c-titin,in chicken epithelial brush border and human blood platelet extracts that binds ,-actinin and organizes arrays of myosin II bipolar filaments in vitro. RT-PCR analysis of total RNA from human megakaryoblastic (CHRF-288-11) and mouse fibroblast (3T3) nonmuscle cells reveal sequences identical to known titin gene exon sequences that encode parts of the Z-line, I-band, PEVK domain, A-band, and M-line regions of striated muscle titins. In the nonmuscle cells, these sequences are differentially spliced in patterns not reported for any striated muscle titin isoform. Rabbit polyclonal antibodies raised against expressed protein fragments encoded by the Z-repeat and kinase domain regions react with the c-titin band in Western blot analysis of platelet extracts and immunoprecipitate c-titin in whole platelet extracts. Immunofluorescent localization demonstrates that the majority of the c-titin colocalizes with ,-actinin and actin in 3T3 and Indian Muntjac deer skin fibroblast stress fibers. Our results suggest that differential expression of titin gene exons in nonmuscle cells yields multiple novel isoforms of the protein c-titin that are associated with the actin stress fiber structures. Cell Motil. Cytoskeleton 2007. © 2007 Wiley-Liss, Inc. [source]

Dystrophin upregulation in pressure-overloaded cardiac hypertrophy in rats

CYTOSKELETON, Issue 1 2003
Masato Maeda
Abstract Dystrophin is a cytoskeletal protein localized to the sarcolemma of skeletal and cardiac muscle, and neurons. We have recently demonstrated that a significant cardiac damage including myocytes injury, inflammation, and fibrosis, was found in dystrophin-deficient myocardium during pressure overload [Kamogawa et al., 2001: Cardiovasc Res 50:509,515]. However, little is known about how the cardiac sarcolemmal cytoskeleton produces qualitative and quantitative changes in response to pressure overload. Accordingly, we investigated dystrophin gene expression and protein accumulation during cardiac hypertrophy. Cardiac hypertrophy was produced by banding of the abdominal aorta of rats. Total RNA from the left ventricle of the heart was used for a quantitative reverse transcription-polymerase chain reaction (RT-PCR). Dystrophin mRNA expression significantly increased by 33 ± 18% at 1 day (P < 0.05) and 45 ± 19% at 2 days (P < 0.01) after banding, while G3PDH mRNA showed no significant change. RT-PCR for dystrophin tissue-specific exon 1 revealed that only muscle type promoter, but not non-muscle type promoter (brain and Purkinje-cell type), was activated immediately after banding. Immunohistochemistry for dystrophin showed intense cellular membrane staining with an increase in the perimeter of the myocytes by 14% at 3 days (46.3 ,m, P < 0.01) and 19% at 7 days (51.2 ,m, P < 0.01) after banding. Western blotting also showed dystrophin protein increased by 14 ± 6% at 2 days (P < 0.05) and by 32 ± 10% at 3 days (P < 0.01) after aortic banding. In conclusion, upregulation of dystrophin mRNA expression and protein accumulation occurs in response to cardiac hypertrophy. These data and the vulnerability of dystrophin-deficient myocardium to pressure overload suggest that dystrophin could play an important role in maintaining the integrity of the sarcolemma. Cell Motil. Cytoskeleton 55:26,35, 2003. © 2003 Wiley-Liss, Inc. [source]

Schizophrenia; from structure to function with special focus on the mediodorsal thalamic prefrontal loop

ACTA PSYCHIATRICA SCANDINAVICA, Issue 5 2009
B. Pakkenberg
Objective:, To describe structural and biochemical evidence from postmortem brains that implicates the reciprocal connections between the mediodorsal thalamic nucleus and the prefrontal cortex in cognitive symptoms of schizophrenia. Method:, The estimation of the regional volumes and cell numbers was obtained using stereological methods. The biochemical analyses of molecular expression in postmortem brain involve quantitative measurement of transcripts and proteins by in-situ (RNA) or Western blot/autoradiography in brains from patients with schizophrenia and comparison subjects. Results:, Stereological studies in postmortem brain from patients with schizophrenia have reported divergent and often opposing findings in the total number of neurons and volume of the mediodorsal (MD) thalamic nucleus, and to a lesser degree in its reciprocally associated areas of the prefrontal cortex. Similarly, quantitative molecular postmortem studies have found large inter-subject and between-study variance at both the transcript and protein levels for receptors and their interacting molecules of several neurotransmitter systems in these interconnected anatomical regions. Combined, large variation in stereological and molecular studies indicates a complex and heterogeneous involvement of the MD thalamic-prefrontal loop in schizophrenia. Conclusion:, Based on a considerable heterogeneity in patients suffering from schizophrenia, large variation in postmortem studies, including stereological and molecular postmortem studies of the MD thalamus and frontal cortex, might be expected and may in fact partly help to explain the variable endophenotypic traits associated with this severe psychiatric illness. [source]

Delivery of small interfering RNA with a synthetic collagen poly(Pro-Hyp-Gly) for gene silencing in vitro and in vivo

DEVELOPMENT GROWTH & DIFFERENTIATION, Issue 8 2010
Taro Adachi
Silencing gene expression by small interfering RNAs (siRNAs) has become a powerful tool for the genetic analysis of many animals. However, the rapid degradation of siRNA and the limited duration of its action in vivo have called for an efficient delivery technology. Here, we describe that siRNA complexed with a synthetic collagen poly(Pro-Hyp-Gly) (SYCOL) is resistant to nucleases and is efficiently transferred into cells in vitro and in vivo, thereby allowing long-term gene silencing in vivo. We found that the SYCOL-mediated local application of siRNA targeting myostatin, coding a negative regulator of skeletal muscle growth, in mouse skeletal muscles, caused a marked increase in the muscle mass within a few weeks after application. Furthermore, in vivo administration of an anti-luciferase siRNA/SYCOL complex partially reduced luciferase expression in xenografted tumors in vivo. These results indicate a SYCOL-based non-viral delivery method could be a reliable simple approach to knockdown gene expression by RNAi in vivo as well as in vitro. [source]

RNA interference by expressing short hairpin RNA in the Ciona intestinalis embryo

DEVELOPMENT GROWTH & DIFFERENTIATION, Issue 6 2008
Aya Nishiyama
We carried out RNA interference by expressing short hairpin RNA (shRNA) in the Ciona intestinalis embryo. For this purpose, we identified a gene encoding U6 small nuclear RNA (snRNA) in the C. intestinalis genome. The 1-kb sequence upstream of the U6 snRNA gene was sufficient for directing transcription of short RNA as revealed by Northern blot hybridization. An shRNA-expressing plasmid vector was constructed, in which shRNA-encoding oligonucleotides are inserted downstream of the U6 promoter. An shRNA that contained a sequence homologous to the C. intestinalis tyrosinase gene (Ci-tyrosinase) suppressed melanization of pigment cells in the brain of morphologically normal tailbud embryos. An shRNA that perfectly matched the translated sequence of enhanced green fluorescent protein (EGFP) (a mutant type of Aequorea victoria green fluorescent protein) suppressed the expression of the coelectroporated EGFP transgene. These results suggest that the expression of shRNA interferes with functions of both endogenous and exogenous genes. The shRNA-expressing plasmid constructed in the present study provides an easy and inexpensive alternative for the functional analysis of genes in ascidian embryos. [source]

Identification of asymmetrically localized transcripts along the animal,vegetal axis of the Xenopus egg

DEVELOPMENT GROWTH & DIFFERENTIATION, Issue 8 2005
Kensuke Kataoka
In many organisms, proper embryo development depends on the asymmetrical distribution of mRNA in the cytoplasm of the egg. Here we report comprehensive screening of RNA localized in the animal or vegetal hemisphere of the Xenopus egg. Macroarrays including over 40 000 independent embryonic cDNA clones, representing at least 17 000 unigenes, were differentially hybridized with labeled probes synthesized from the mRNA of animal or vegetal blastomeres. After two rounds of screening, we identified 33 clones of transcripts that may be preferentially distributed in the vegetal region of the early stage embryo, but transcripts localized in the animal region were not found. To assess the array results, we performed northern blot and quantitative real-time reverse transcription,polymerase chain reaction analysis. As a result, 21 transcripts of the 33 were confirmed to be localized in the vegetal region of the early stage embryo. Whole-mount in situ hybridization analysis revealed that 11 transcripts, including 7 previously reported genes, were localized in the vegetal hemisphere of the egg. These 11 transcripts were categorized into three groups according to their expression patterns in the egg. The first group, which contained four transcripts, showed uniform expression in the vegetal hemisphere, similar to VegT. The second group, which contained three transcripts, showed gradual expression from the vegetal pole to the equator, similar to Vg1. The last group, which contained three transcripts, was expressed at the germ plasm, similar to Xdazl. One transcript, Xwnt11, showed both the second and the third expression patterns. [source]

Cloning and characterization of cDNA for syndecan core protein in sea urchin embryos

DEVELOPMENT GROWTH & DIFFERENTIATION, Issue 5 2000
Kazuo Tomita
The cDNA for the core protein of the heparan sulfate proteoglycan, syndecan, of embryos of the sea urchin Anthocidaris crassispina was cloned and characterized. Reverse transcription,polymerase chain reaction (RT-PCR) was used with total ribonucleic acid (RNA) from late gastrula stage embryos and degenerate primers for conserved regions of the core protein, to obtain a 0.1 kb PCR product. A late gastrula stage cDNA library was then screened using the PCR product as a probe. The clones obtained contained an open reading frame of 219 amino acid residues. The predicted product was 41.6% identical to mouse syndecan-1 in the region spanning the cytoplasmic and transmembrane domains. Northern analysis showed that the transcripts were present in unfertilized eggs and maximum expression was detected at the early gastrula stage. Syndecan mRNA was localized around the nuclei at the early cleavage stage, but was then found in the ectodermal cells of the gastrula embryos. Western blotting analysis using the antibody against the recombinant syndecan showed that the proteoglycan was present at a constant level from the unfertilized egg stage through to the pluteus larval stage. Immunostaining revealed that the protein was expressed on apical and basal surfaces of the epithelial wall in blastulae and gastrulae. [source]

Involvement of BMP-4/msx-1 and FGF pathways in neural induction in the Xenopus embryo

DEVELOPMENT GROWTH & DIFFERENTIATION, Issue 4 2000
Akihiko Ishimura
The msx homeodomain protein is a downstream transcription factor of the bone morphogenetic protein (BMP)-4 signal and a key regulator for neural tissue differentiation. Xmsx-1 antagonizes the dorsal expression of noggin and cerberus, as revealed by in situ hybridization and reverse transcription,polymerase chain reaction assays. In animal cap explants, Xmsx-1 and BMP-4 inhibit the neural tissue differentiation induced by noggin or cerberus. A loss-of-function study using the Xmsx-1/VP-16 fusion construct indicated that neural tissue formation was directly induced by the injection of fusion ribonucleic acid, although the expression of neural cell adhesion molecule (N-CAM) in the cap was less than that in the cap injected with tBR or noggin. In contrast to the single cap assay, unexpectedly, both BMP-4 and Xmsx-1 failed to inhibit neurulation in the ectodermal explants to which the organizer mesoderm was attached. The results of cell-lineage tracing experiments indicated that the neural cells were differentiated from the animal pole tissue where the excess RNA of either BMP-4 or Xmsx-1 was injected, whereas notochord was differentiated from the organizer mesoderm. Neural tissue differentiated from BMP-4 -injected ectodermal cells strongly expressed posterior neural markers, such as hoxB9 and krox20, suggesting that the posterior neural cells differentiated regardless of the existence of the BMP signal. The introduction of a dominant-negative form of the fibroblast growth factor (FGF) receptor (XFD) into the ectodermal cells drastically reduced the expression of pan and posterior neural markers (N-CAM and hoxB-9) if co-injected with BMP-4 RNA, although XFD alone at the same dose did not shut down the expression of N-CAM in the combination explants. Therefore, it is proposed that an FGF-related molecule was involved in the direct induction of posterior neural tissue in the inducing signals from the organizer mesoderm in vivo. [source]

Spatio-temporal expression of Xenopus vasa homolog, XVLG1, in oocytes and embryos: The presence of XVLG1 RNA in somatic cells as well as germline cells

DEVELOPMENT GROWTH & DIFFERENTIATION, Issue 2 2000
Kohji Ikenishi
The expression of Xenopus vasa homolog or XVLG1 was examined in oocytes and embryos by whole-mount in situ hybridization and reverse transcription,polymerase chain reaction (RT-PCR). To confirm the results in embryos, both methods were also applied to explants of germ plasm-bearing cells (GPBC) from 32-cell embryos and to those of partial embryos deprived of GPBC. By hybridization, XVLG1 ribonucleic acid (RNA) was shown to be present throughout the cytoplasm in oocytes at stages I,III, except for the mitochondrial cloud. It was barely recognizable in a portion of germline cells of embryos at specific stages, notwithstanding that XVLG1 protein was present in those cells almost throughout their life-span. A weak signal for the RNA was detectable in some of the presumptive primordial germ cells (pPGC, descendants of GPBC from the gastrula stage onward) from the late gastrula (stage 12) to the hatching tadpole stage (stage 33/34), and in some of the PGC at stages 49,50. The results for pPGC were confirmed by the hybridization of explants of GPBC at equivalent stages in control embryos. In contrast, XVLG1 RNA was detected in certain somatic cells of embryos until stage 46. These observations were supported in part by the results of RT-PCR for embryos and explants. The possible role of the product of XVLG1 was reconsidered given its presence in both germline and somatic cells. [source]

Vanishing white matter disease: A review with focus on its genetics

DEVELOPMENTAL DISABILITIES RESEARCH REVIEW, Issue 2 2006
Jan C. Pronk
Abstract Leukoencephalopathy with vanishing white matter (VWM) is an autosomal recessive brain disorder, most often with a childhood onset. Magnetic resonance imaging and spectroscopy indicate that, with time, increasing amounts of cerebral white matter vanish and are replaced by fluid. Autopsy confirms white matter rarefaction and cystic degeneration. The process of localization and identification of the first two genes related to VWM, EIF2B5 and EIF2B2, was facilitated by two founder effects in the Dutch population. EIF2B5 and EIF2B2 encode the , and , subunits of translation initiation factor eIF2B. Soon it was shown that mutations in all five eIF2B subunit genes can cause VWM. EIF2B is essential for the initiation of translation of RNA into protein and is involved in regulation of the process, especially under stress conditions, which may explain the sensitivity to stress conditions observed in VWM patients. The pathophysiology of the disease is still poorly understood. MRDD Research Reviews 2006;12:123,128. © 2006 Wiley-Liss, Inc. [source]

Identification of germ plasm-associated transcripts by microarray analysis of Xenopus vegetal cortex RNA

DEVELOPMENTAL DYNAMICS, Issue 6 2010
Tawny N. Cuykendall
Abstract RNA localization is a common mechanism for regulating cell structure and function. Localized RNAs in Xenopus oocytes are critical for early development, including germline specification by the germ plasm. Despite the importance of these localized RNAs, only approximately 25 have been identified and fewer are functionally characterized. Using microarrays, we identified a large set of localized RNAs from the vegetal cortex. Overall, our results indicate a minimum of 275 localized RNAs in oocytes, or 2,3% of maternal transcripts, which are in general agreement with previous findings. We further validated vegetal localization for 24 candidates and further characterized three genes expressed in the germ plasm. We identified novel germ plasm expression for reticulon 3.1, exd2 (a novel exonuclease-domain encoding gene), and a putative noncoding RNA. Further analysis of these and other localized RNAs will likely identify new functions of germ plasm and facilitate the identification of cis -acting RNA localization elements. Developmental Dynamics 239:1838,1848, 2010. © 2010 Wiley-Liss, Inc. [source]

Expression of AP-2, in the developing chick retina

DEVELOPMENTAL DYNAMICS, Issue 11 2008
Xiaodong Li
Abstract AP-2 is a family of transcription factors that play important roles during embryonic development. Two AP - 2 genes, AP - 2, and AP - 2,, have previously been characterized in chick retina. Here, we demonstrate that a third member of the chicken AP-2 family, AP - 2,, is primarily expressed in the retina and brain, with highest levels at embryonic days 7 to 11. By in situ hybridization and immunohistochemical analysis, we show that AP - 2, RNA and protein are found in a subset of ganglion cells in embryonic chick retina. Co-immunostaining with anti-Brn3a and anti,AP-2, antibodies indicates that approximately one-third of Brn3a-positive ganglion cells express AP-2,. AP - 2, RNA but not AP-2, protein is also found in cells located in the outer half of the inner nuclear layer. The spatial and temporal distribution of AP-2, protein in the retina suggests a transient role in a subset of late-born ganglion cells likely involving axonal trafficking or pathfinding. Developmental Dynamics 237:3210,3221, 2008. © 2008 Wiley-Liss, Inc. [source]

Androgen receptor gene expression in the developing and adult zebrafish brain

DEVELOPMENTAL DYNAMICS, Issue 10 2008
Daniel A. Gorelick
Abstract Androgens play a central role in the regulation of male sexual differentiation and behavior in many vertebrates, including zebrafish. Their signaling is mediated by activation of the androgen receptor. A single androgen receptor (ar) gene was recently identified in zebrafish, which encodes a protein that binds androgens in vitro. However, the tissue-specific expression pattern of this receptor in vivo has not been described. Using whole-mount RNA in situ hybridization, we characterized expression of the ar gene in developing zebrafish and in the adult brain. In embryos, transcripts were found in the presumptive pronephros and in olfactory placodes. By 3,5 days postfertilization, ar transcripts were also detected in the pineal organ anlage and the retina. In the adult brain, ar was expressed in discrete regions of the telencephalon, in the preoptic area, and throughout the periventricular hypothalamus, regions previously implicated in the regulation of sexually dimorphic behaviors in mammals. Developmental Dynamics 237:2987,2995, 2008. © 2008 Wiley-Liss, Inc. [source]

Genes involved in the RNA interference pathway are differentially expressed during sea urchin development

DEVELOPMENTAL DYNAMICS, Issue 11 2007
Jia L. Song
Abstract RNA-mediated interference (RNAi) is a conserved gene silencing mechanism that involves double-stranded RNA as a signal to trigger the sequence-specific degradation of target mRNA, resulting in posttranscriptional silencing and/or translational repression. Bioinformatic searches in the sea urchin genome database identified homologs of Drosha, DGCR5, Dicer, TRBP, Exportin-5, and Argonautes. Quantitative, real-time polymerase chain reaction indicated that all mRNA accumulate in eggs and in variable levels throughout early development. Whole-mount in situ RNA hybridization showed that all of the important players of the RNAi silencing pathway have abundant mRNA accumulation in oocytes and eggs, but have distinct spatial and temporal expression patterns throughout development. Sequence analysis revealed that each of the four Argonautes examined contain conserved residues important for RNAseH activity within the Piwi domain. This study elucidated that genes involved in the RNAi silencing pathway have dynamic expression and, thus, may have regulatory roles during germ cell development and embryogenesis. Developmental Dynamics 236:3180,3190, 2007. © 2007 Wiley-Liss, Inc. [source]