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Spatiotemporal Expression (spatiotemporal + expression)
Selected AbstractsSpatiotemporal expression of NGFR during pre-natal human tooth developmentORTHODONTICS & CRANIOFACIAL RESEARCH, Issue 2 2002KB Becktor Structured Abstract Authors, Becktor KB, Hansen BF, Nolting D, Kjær I. Objectives, The relation between nerve growth factor receptor (NGFR) in the human pre-natal tooth buds and the dental follicle was investigated. In particular, we sought to determine if there is a specific pattern of p75NGFR expression in developing human tooth buds and their surrounding tissue. Setting and Sample Population, The Department of Orthodontics at Copenhagen University, Denmark. Histological sections from 11 fetuses, aged 11,21 gestational weeks. Method, The sections were studied by conventional immunohistochemistry. Results, Specific spatiotemporal patterns of p75NGFR reactions were observed in the tooth buds and dental follicle: Before matrix production by the ameloblasts, the entire inner enamel epithelium and the entire dental follicle display p75NGFR immunoreactivity; after matrix production is initiated, the immunoreactivity of the matrix producing cells is lost, as is that of the dental follicle adjacent to these matrix-producing cells. Conclusion, A unique spatiotemporal distribution of NGFR in the pre-eruptive human tooth bud was demonstrated. [source] Spatiotemporal expression of chemokines and chemokine receptors in experimental anti-myeloperoxidase antibody-mediated glomerulonephritisCLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 1 2009B. S. Van Der Veen Summary Myeloperoxidase (MPO)-anti-neutrophil cytoplasmic autoantibody (ANCA)-associated necrotizing crescentic glomerulonephritis (NCGN) is characterized by abundant leucocyte infiltration. Chemokines are chemotactic cytokines involved in receptor-mediated recruitment of leucocytes. Our objective was to analyse spatiotemporal gene expression of chemokines and chemokine receptors in anti-MPO-mediated NCGN, to find potential targets for intervening with leucocyte influx. NCGN was induced in mice by co-administration of anti-MPO immunoglobulin (Ig)G and lipopolysaccharide. mRNA expression levels of chemokines and chemokine receptors were analysed in whole kidney lysates as well as in laser microdissected glomeruli and tubulo-interstitial tissue 1 and 7 day(s) after NCGN induction. Several chemokines and chemokine receptors were induced or up-regulated in anti-MPO-mediated NCGN, both on day 1 (chemokines CCL3, 5; CXCL2, 5, 13; receptor CXCR2) and on day 7 (chemokines CCL2, 5, 7, 8, 17, 20; CXCL1, 2, 5, 10; CX3CL1; receptors CCR2, 8; CX3CR1). The expression levels of most chemokines and receptors were higher in glomeruli than in the tubulo-interstitium. Because of the temporal induction of CXCR2 on day 1, we hypothesized CXCR2 as a potential target for treatment in anti-MPO-induced NCGN. Inhibition of CXCR2 using a goat-anti-CXCR2 serum prior to NCGN induction increased glomerular neutrophil influx but did not affect crescent formation and albuminuria. In conclusion, expression levels of various chemokines and chemokine receptors were increased in anti-MPO NCGN, and expressed particularly in glomeruli. These chemokines and receptors may serve as potential targets for treatment. Inhibition of a single target, CXCR2, did not attenuate anti-MPO NCGN. Combinatorial interventions may be necessary to avoid redundancy. [source] Transient expression of thyroid hormone nuclear receptor TR,2 sets S opsin patterning during cone photoreceptor genesisDEVELOPMENTAL DYNAMICS, Issue 5 2007M.L. Applebury Abstract Cone photoreceptors in the murine retina are patterned by dorsal repression and ventral activation of S opsin. TR,2, the nuclear thyroid hormone receptor , isoform 2, regulates dorsal repression. To determine the molecular mechanism by which TR,2 acts, we compared the spatiotemporal expression of TR,2 and S opsin from embryonic day (E) 13 through adulthood in C57BL/6 retinae. TR,2 and S opsin are expressed in cone photoreceptors only. Both are transcribed by E13, and their levels increase with cone genesis. TR,2 is expressed uniformly, but transiently, across the retina. mRNA levels are maximal by E17 at completion of cone genesis and again minimal before P5. S opsin is also transcribed by E13, but only in ventral cones. Repression in dorsal cones is established by E17, consistent with the occurrence of patterning during cone cell genesis. The uniform expression of TR,2 suggests that repression of S opsin requires other dorsal-specific factors in addition to TR,2. The mechanism by which TR,2 functions was probed in transgenic animals with TR,2 ablated, TR,2 that is DNA binding defective, and TR,2 that is ligand binding defective. These studies show that TR,2 is necessary for dorsal repression, but not ventral activation of S opsin. TR,2 must bind DNA and the ligand T3 (thyroid hormone) to repress S opsin. Once repression is established, T3 no longer regulates dorsal S opsin repression in adult animals. The transient, embryonic action of TR,2 is consistent with a role (direct and/or indirect) in chromatin remodeling that leads to permanent gene silencing in terminally differentiated, dorsal cone photoreceptors. Developmental Dynamics 236:1203,1212, 2007. © 2007 Wiley-Liss, Inc. [source] Early evolution of a homeobox gene: the parahox gene Gsx in the Cnidaria and the BilateriaEVOLUTION AND DEVELOPMENT, Issue 4 2003John R. Finnerty Summary Homeobox transcription factors are commonly involved in developmental regulation in diverse eukaryotes, including plants, animals, and fungi. The origin of novel homeobox genes is thought to have contributed to many evolutionary innovations in animals. We perform a molecular phylogenetic analysis of cnox2, the best studied homeobox gene from the phylum Cnidaria, a very ancient lineage of animals. Among three competing hypotheses, our analysis decisively favors the hypothesis that cnox2 is orthologous to the gsx gene of Bilateria, thereby establishing the existence of this specific homeobox gene in the eumetazoan stem lineage, some 650,900 million years ago. We assayed the expression of gsx in the planula larva and polyp of the sea anemone Nematostella vectensis using in situ hybridization and reverse transcriptase polymerase chain reaction. The gsx ortholog of Nematostella, known as anthox2, is expressed at high levels in the posterior planula and the corresponding "head" region of the polyp. It cannot be detected in the anterior planula or the corresponding "foot" region of the polyp. We have attempted to reconstruct the evolution of gsx spatiotemporal expression in cnidarians and bilaterians using a phylogenetic framework. Because of the surprisingly high degree of variability in gsx expression within the Cnidaria, it is currently not possible to infer unambiguously the ancestral cnidarian condition or the ancestral eumetazoan condition for gsx expression. [source] A lophotrochozoan twist gene is expressed in the ectomesoderm of the gastropod mollusk Patella vulgataEVOLUTION AND DEVELOPMENT, Issue 5 2002Alexander J. Nederbragt SUMMARY The twist gene is known to be involved in mesoderm formation in two of the three clades of bilaterally symmetrical animals: viz. deuterostomes (such as vertebrates) and ecdysozoans (such as arthropods and nematodes). There are currently no data on the spatiotemporal expression of this gene in the third clade, the lophotrochozoans (such as mollusks and annelids). To approach the question of mesoderm homology across bilaterians, we decided to analyze orthologs of this gene in the gastropod mollusk Patella vulgata that belongs to the lophotrochozoans. We present here the cloning, characterization, and phylogenetic analysis of a Patella twist ortholog, Pv-twi, and determine the early spatiotemporal expression pattern of this gene. Pv-twi expression was found in the trochophore larva in a subset of the ectomesoderm, one of the two sources of mesoderm in Patella. These data support the idea that twist genes were ancestrally involved in mesoderm differentiation. The absence of Pv-twi in the second mesodermal source, the endomesoderm, suggests that also other genes must be involved in lophotrochozoan mesoderm differentiation. It therefore remains a question if the mesoderm of all bilaterians is homologous. [source] A novel mutation in the GATA4 gene in patients with Tetralogy of Fallot,,HUMAN MUTATION, Issue 3 2006Georges Nemer Abstract In vertebrates, heart formation which integrates different structures and cell types is a complex process that involves a network of genes regulated by transcription factors. Proper spatiotemporal expression of these factors ensure the highly needed tight control of each step in organogenesis. A mistake at any step from cell-commitment to valve formation will have a major impact on heart morphogenesis and function leading to congenital heart disease (CHD). Cardiac abnormalities occur with an incidence of one per 100 live births and represent 25% of all congenital malformations. As an alternative approach to linkage-analysis of familial cases of CHD, we started screening familial and sporadic cases of CHDs in a highly consanguineous population for mutations in genes encoding cardiac-enriched transcription factors. The evolutionarily conserved role of these proteins in cardiac development suggested a role in CHD. In this study, we report a mutation in the gene encoding GATA4, one of the earliest markers of heart development. This mutation was found in two out of 26 patients with Tetralogy of Fallot (TOF), and in none of the 94 patients with different phenotypes included in the study, nor in 223 healthy individuals. The heterozygous mutation results in an amino acid substitution in the first zinc finger of GATA4 that reduced its transcriptional activation of downstream target genes, without affecting GATA4 ability to bind DNA, nor its interaction with ZFPM2. © 2006 Wiley-Liss, Inc. [source] Molecular dynamics of the blood,testis barrier components during murine spermatogenesisMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 7 2010Masataka Chihara The blood,testis barrier (BTB) separates the seminiferous epithelium into the adluminal and basal compartments. During murine spermatogenesis, preleptotene/leptotene spermatocytes migrate from the basal to the adluminal compartment through the BTB during stages VIII,IX. In the present study, we focused on the tight junction (TJ) molecules and analyzed their spatiotemporal expression during the murine seminiferous epithelial cycle. Structural analysis revealed that the principal components of the BTB, for example, claudin-3, claudin-11, occludin, and zonula occludens-1 (ZO-1), were localized at the basal and luminal sides of the preleptotene/leptotene spermatocytes during the migration stages (VIII,IX). Although we detected claudin-11, occludin, and ZO-1 throughout spermatogenesis, claudin-3 was only detected during stages VI,IX. Quantitative PCR using dissected seminiferous tubules from three stages (Early: II,VI, Middle: VII,VIII, Late: IX,I) clarified that the mRNA levels of TJ molecules were not correlated with the histoplanimetrical protein levels during spermatogenesis. Additionally, tubulobulbar complexes, considered to be involved in the internalization of TJ, were observed at the BTB site. Furthermore, a significant reduction in the mRNA levels of genes for the degradation of occludin (Itch) and endocytic recycling (Rab13) were observed during the Late and Middle stages, respectively. Therefore, we hypothesized that the lag between mRNA and protein expression of TJ molecules may be due to posttranslational modulation, for example, tubulobulbar complexes and endocytic recycling processes. In conclusion, these findings indicate that the integrity of the BTB is maintained throughout spermatogenesis, and the stage-specific localization of claudin-3 protein plays an important role in regulating BTB permeability. Mol. Reprod. Dev. 77: 630,639, 2010. © 2010 Wiley-Liss, Inc. [source] Expression of the LIM-homeodomain protein Isl1 in the developing and mature mouse retinaTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 1 2007Yasser Elshatory Abstract The mammalian retina is comprised of six major neuronal cell types and is subdivided into more morphological and physiological subtypes. The transcriptional machinery underlying these subtype fate choices is largely unknown. The LIM-homeodomain protein, Isl1, plays an essential role in central nervous system (CNS) differentiation but its relationship to retinal neurogenesis remains unknown. We report here its dynamic spatiotemporal expression in the mouse retina. Among bipolar interneurons, Isl1 expression commences at postnatal day (P)5 and is later restricted to ON-bipolar cells. The intensity of Isl1 expression is found to segregate the pool of ON-bipolar cells into rod and ON-cone bipolar cells with higher expression in rod bipolar cells. As bipolar cell development proceeds from P5,10 the colocalization of Isl1 and the pan-bipolar cell marker Chx10 reveals the organization of ON-center bipolar cell nuclei to the upper portion of the inner nuclear layer. Further, whereas Isl1 is predominantly a ganglion cell marker prior to embryonic day (E)15.5, at E15.5 and later its expression in nonganglion cells expands. We demonstrate that these Isl1-positive, nonganglion cells acquire the expression of amacrine cell markers embryonically, likely representing nascent cholinergic amacrine cells. Taken together, Isl1 is expressed during the maturation of and is later maintained in retinal ganglion cells and subtypes of amacrine and bipolar cells where it may function in the maintenance of these cells into adulthood. J. Comp. Neurol. 503:182,197, 2007. © 2007 Wiley-Liss, Inc. [source] Post-natal Development of Perineuronal Nets in the Retrosplenial Cortex of Albino RatANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2005R. Sayed The brain extracellular matrix (ECM) has attracted growing interest due to its highly regulated spatiotemporal expression during development and maturation of central nervous system. The present study deals with the post-natal appearance and transformation into adult distribution patterns of the ECM components related to proteoglycans (PGs) and glycoproteins (GPs) in the retrosplenial cortex (RSC) of albino rats at birth (P0), 1 week (P1), P2, P3, P4, P5, P6, P7 and P8. The differentiating PGs and GPs components of the ECM were shown to make their appearance as early as 1,2 weeks post-natally. At this developmental stage, these components of the ECM appeared in association with some neurons and glia cells or diffusely localized at the neutrophill. Interestingly, Golgi complexes of labelled neurons were usually stained with lectin VVA or WFA, and this labelling dramatically disappeared on reaching P4. During P2,3, the pericoated neuronal cells underwent a progressive increment in number, and presented an inside-out pattern of migration and differentiation (toward the V-II cortical layers). On reaching P4, most of the coated neurons appeared distributed into the cortical layer IV and II. At a later stage (P5,8), the overall density and intensity of labelled neurons progressively increased and apparently reached the adult stage of development. They also displayed the usual differential labelling characteristics, after using the cationic iron colloid/lectin staining, for the first time at this juncture. The present findings indicated that the perineuronal ECM components are significantly correlated with age and suggest a possible developmental or biological significance including promotion of migration, as well as functional maturation of the retrosplenial neurons. [source] | |||||||||||||