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Mutant Lines (mutant + line)

Distribution by Scientific Domains

Life Sciences	72%

Selected Abstracts

The Interaction of Plasmodiophora brassicae and Arabidopsis thaliana: Parameters for Disease Quantification and Screening of Mutant Lines

JOURNAL OF PHYTOPATHOLOGY, Issue 11-12 2002
J. Siemens
Abstract The soil-borne obligate pathogen Plasmodiophora brassicae causes clubroot disease in species of Brassicaceae, including Arabidopsis thaliana. The host,pathogen interaction was studied with respect to the age of the plant at the time point of inoculation and to different infection pressures in order to establish a standardization of infection parameters and evaluation of disease extent for A. thaliana lines. Spore number per root weight, root and shoot weight of inoculated and non-inoculated plants as well as infection rate and disease index (DI) were analysed and correlated. The disease extent of different lines was comparable as measured by the relation of root weight of inoculated and non-inoculated plants (Ri/Rni index) and the DI. Most of the 71 screened A. thaliana lines turned out to be susceptible. However, the mutant lines tu8, tu3, det1-1, and rhd3-1 showed a certain degree of tolerance under specific culture conditions. The reactions of rhd3-1 indicate that hypertrophy is a prerequisite for maturation of the pathogen. The reactions of the tu3 and tu8 mutants indicate a role of indole glucosinolates and indole-3-acetonitrile/IAA in development of clubroot disease. [source]

Nestin expression in pancreatic endocrine and exocrine cells of mice lacking glucagon signaling

DEVELOPMENTAL DYNAMICS, Issue 4 2007
Mamdouh H. Kedees
Abstract Nestin, a marker of neural stem cells, is also expressed by cells located in the epithelium of the pancreatic primordium and by a subpopulation of exocrine cells but not by endocrine cells. These findings raised the possibility that the pancreatic epithelium is heterogeneous and comprised of subpopulations of exocrine/nestin-positive and endocrine/nestin-negative precursor cells. We examined this issue in two mutant mouse models characterized by protracted expression of several embryonal properties in islet cells. One mutant line comprises mice lacking mature glucagon due to abrogation of proprotein convertase-2 (PC2,/,), responsible for the conversion of proglucagon into glucagon, while the second line consists of mice with a global deletion of the glucagon receptor (Gcgr,/,). We demonstrate that nestin is transiently expressed by acinar cells and by insulin and glucagon cells of islets of both lines of mice. In addition, the lack of glucagon signaling increased nestin mRNA levels in pancreas of mutant embryos and adult mice. We conclude that nestin+ cells located in the pancreatic primordium generate the cells of the endocrine and exocrine lineages. Furthermore, our results suggest that nestin expression is regulated by glucagon signaling. Developmental Dynamics 236:1126,1133, 2007. © 2007 Wiley-Liss, Inc. [source]

Metabolic phenotyping of mouse mutants in the German Mouse Clinic

INTEGRATIVE ZOOLOGY (ELECTRONIC), Issue 3 2006
Ralf ELVERT
Abstract The German Mouse Clinic was established as a phenotyping center to provide the scientific community with systematic standardized phenotyping of mouse models from various genetic backgrounds. We found metabolic phenotypes in nine out of 20 mutant lines screened in a primary screen. Based on these findings, the mutants were analyzed in secondary and tertiary screens. Mice of a sample mutant line, isolated from the ENU-screen at the National Research Center for Environment and Health in Munich, were found to have lower body weight, consume less food, but have higher ratios of metabolized energy per unit body weight compared with their wild-type littermates. Basal metabolic rate and heat production were simultaneously increased by 16,18%, whereas body fat content was reduced by 11,16%. The combination of various parameters of energy consumption, expenditure and energy storage illustrate the metabolic demands of the sample mutant mouse line and demonstrate the utility of the powerful phenotyping tool used at the German Mouse Clinic. [source]

Expression patterns of low temperature responsive genes in a dominant ABA-less-sensitive mutant line of common wheat

PHYSIOLOGIA PLANTARUM, Issue 4 2006
Fuminori Kobayashi
Abscisic acid (ABA) plays important role in mediating stress responses and in acquiring desiccation tolerance and dormancy of plant seeds. To study roles of ABA in cold acclimation and freezing tolerance in wheat, expression profiles of Cor/Lea and their putative transcription factor (TF) genes were analysed using a dominant mutation line of common wheat EH47-1 lacking seed dormancy. The mutant line was less sensitive to exogenous ABA than the original line as judged by the magnitude of ABA inhibition of seedling growth. Expression analysis of Cor/Lea and TF genes however, showed that more transcripts were present in ABA-treated seedlings of the mutant line. In developing caryopses, the same tendency was observed. The mutant line showed no changes in the cold acclimation ability, but it showed a higher level of freezing tolerance than the original line without cold acclimation. No significant differences were observed in the expression profiles of Cor/Lea and TF genes during cold acclimation between the two lines. Our results imply the presence of an unknown ABA-dependent cold responsive pathway, which enhances the basal level of freezing tolerance by a dominant mutation in EH47-1. [source]

4142: The Sanger Mouse Genetics Programme: high throughput characterisation of knockout mice

ACTA OPHTHALMOLOGICA, Issue 2010
AK GERDIN
Purpose The Sanger Mouse Genetics Programme (MGP) aims to make a significant impact on our understanding of the function of genes and their role in disease by generating, characterising and archiving in the order of 200 lines of knockout mice per year, including 40 lines as part of the EUMODIC consortium. The phenotyping screens employed include a wide range of assays relevant to key disease areas including diabetes, obesity, hearing and vision disorders, immune disorders, pain and motor function. The data generated by the primary screen will help to further the understanding of the interplay of genes and disease and will provide an insight into the various underlying biological pathways. All phenotyping data and biological resources generated by the programme are openly available to the scientific community. Methods Eye morphology is routinely assessed using the Slit Lamp and Ophthalmoscope and images are collected when abnormalities are identified. Expression profiling via the lacZ reporter gene is performed for each mutant line in adults and at E14.5. Results To date, the eye screen has been performed on over 180 mutant lines. Here we report examples of novel eye-related abnormalities identified by the eye morphology, embryonic lethality and/or expression screens performed by the Sanger MGP. We will present how to identify a potentially interesting mouse mutant on our database and discuss the impact our knock-out mouse models might have on your research. [source]

Metabolic phenotyping of mouse mutants in the German Mouse Clinic

The Interaction of Plasmodiophora brassicae and Arabidopsis thaliana: Parameters for Disease Quantification and Screening of Mutant Lines

Characterization of four rice mutants with alterations in the defence response pathway

MOLECULAR PLANT PATHOLOGY, Issue 1 2005
M. A. CAMPBELL
SUMMARY A fast-neutron mutagenized population of rice seedlings was screened with Magnaporthe grisea, the causal agent of rice blast disease, to identify mutants with alterations in the defence response. Three mutant lines, ebr1, ebr2 and ebr3 (enhanced blast resistance) were identified that display enhanced resistance to M. grisea. ebr1 and ebr3 also confer enhanced resistance to the bacterial pathogen Xanthomonas oryzae pv. oryzae (Xoo). ebr3 develops a lesion mimic (LM) phenotype upon inoculation with M. grisea, and the phenotype is also induced by a shift in environmental conditions. The fourth mutant line, ncr1 (necrosis in rice), has an LM phenotype under all conditions tested and lacks enhanced resistance to either M. grisea or Xoo. Complementation testing using the mutant lines ebr3 and ncr1 indicates that the ebr3 and ncr1 loci are nonallelic and recessive. ebr1 and ebr2 display no alterations in expression of the rice pathogenesis-related (PR) genes PBZ1 and PR1, compared to wild-type CO39. ebr3 has an elevated expression of PBZ1 and PR1 only in tissue displaying the LM phenotype. ncr1 strongly expresses PBZ1 in tissue displaying the LM phenotype, whereas PR1 expression in this tissue is similar to wild-type CO39. [source]

Characterisation of aurone biosynthesis in Antirrhinum majus

PHYSIOLOGIA PLANTARUM, Issue 4 2006
Kevin M. Davies
Aurones are bright yellow flavonoids produced in petals of a limited range of plant species, including Antirrhinum majus. The biosynthesis of aurones is thought to occur by the action of aureusidin synthase (AUS), and possibly aureusidin 7- O -glucosyltransferase (A7GT). The temporal and spatial occurrence of AUS and A7GT transcript was examined in wild-type A. majus and two mutant lines; sulfurea, which has increased aurone production in petals, and violacea, which has reduced aurone production. AUS and A7GT transcript abundance was similar in all three lines, increasing during flower development coincident with yellow coloration. The spatial pattern of AUS occurrence was also similar in all three lines, being spatially restricted to the inner epidermis of the face and throat of the lower petal. A new recessive line (CFR1011) with greatly reduced aurone production in all parts of the petal was identified by ethylmethanesulfonate mutagenesis of the homozygous recessive sulfurea line. Transcript abundance for AUS was not changed in the CFR1011 line compared with the wild-type line, and neither were any point mutations detected in the coding sequences for AUS or A7GT. Thus, the sulfurea, violacea and CFR1011 mutations do not seem to control aurone production through a change in transcript abundance of the predicted biosynthetic genes AUS or A7GT. To examine AUS gene regulation further, the putative AUS gene promoter region was isolated and compared with other A. majus flavonoid gene promoters. A number of conserved potential regulatory regions were identified, in particular a consensus site for the MYB-type transcription factors. [source]

Direct analysis of single leaf disks for chemopreventive glucosinolates

PHYTOCHEMICAL ANALYSIS, Issue 3 2002
Qiaomei Wang
Abstract Natural isothiocyanates, produced during plant tissue damage from methionine-derived glucosinolates, are potent inducers of mammalian phase 2 detoxification enzymes such as quinone reductase (QR). A greatly simplified bioassay for glucosinolates based on induction and colorimetric detection of QR activity in murine hepatoma cells is described. It is demonstrated that excised leaf disks of Arabidopsis thaliana (ecotype Columbia) can directly and reproducibly substitute for cell-free leaf extracts as inducers of murine QR, which reduces sample preparation to a minimum and maximizes throughput. A comparison of 1 and 3,mm diameter leaf disks indicated that QR inducer potency was proportional to disk circumference (extent of tissue damage) rather than to area. When compared to the QR inducer potency of the corresponding amount of extract, 1,mm leaf disks were equally effective, whereas 3,mm disks were 70% as potent. The QR inducer potency of leaf disks correlated positively with the content of methionine-derived glucosinolates, as shown by the analysis of wild-type plants and mutant lines with lower or higher glucosinolate content. Thus, the microtitre plate-based assay of single leaf disks provides a robust and inexpensive visual method for rapidly screening large numbers of plants in mapping populations or mutant collections and may be applicable to other glucosinolate-producing species. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Identification of barley mutants in the cultivar ,Lux' at the Dhn loci through TILLING

PLANT BREEDING, Issue 4 2009
S. Lababidi
Abstract TILLING is a reverse genetic strategy that allows screening for mutations in genes with known sequences in a plant mutant population. A TILLING population has been developed for the Danish barley variety ,Lux' (Hordeum vulgare L.), by using sodium azide to induce mutations. Scoring of four visible phenotypic characters of barley seedling in reference to the parental cultivar ,Lux' in the M3 plants showed over 3.5% lethality. A series of pool ratios of mixed DNA from mutant lines were tested and 10-fold pools appeared to be the practical mixing ratio for the detection of fragments in the 500,700 bp range. Two of the 13 known dehydrin genes, Dhn12 and Dhn13, respectively, were examined and five independent missense mutations were obtained from a population of 9575 barley mutant plants. This corresponds to a mutation density of approximately one mutation every two and half million base pairs for these two genes. The mutant population of approximately 10 000 lines was screened for mutations in two genes in a short time due to high pooling ratio. [source]

Over-expression of different aldehyde dehydrogenase genes in Arabidopsis thaliana confers tolerance to abiotic stress and protects plants against lipid peroxidation and oxidative stress

PLANT CELL & ENVIRONMENT, Issue 6 2006
SIMEON O. KOTCHONI
ABSTRACT Aldehyde dehydrogenases (ALDHs) play a major role in the detoxification processes of aldehydes generated in plants when exposed to abiotic stress. In previous studies, we have shown that the Arabidopsis thaliana ALDH3I1 gene is transcriptionally activated by abiotic stress, and over-expression of the ALDH3I1 gene confers stress tolerance in transgenic plants. The A. thaliana genome contains 14 ALDH genes expressed in different sub-cellular compartments and are presumably involved in different reactions. The purpose of this study was to compare the potential of a cytoplasmic and a chloroplastic stress-inducible ALDH in conferring stress tolerance under different conditions. We demonstrated that constitutive or stress-inducible expression of both the chloroplastic ALDH3I1 and the cytoplasmic ALDH7B4 confers tolerance to osmotic and oxidative stress. Stress tolerance in transgenic plants is accompanied by a reduction of H2O2 and malondialdehyde (MDA) derived from cellular lipid peroxidation. Involvement of ALDHs in stress tolerance was corroborated by the analysis of ALDH3I1 and ALDH7B4 T-DNA knockout (KO) mutants. Both mutant lines exhibited higher sensitivity to dehydration and salt than wild-type (WT) plants. The results indicate that ALDH3I1 and ALDH7B4 not only function as aldehyde-detoxifying enzymes, but also as efficient reactive oxygen species (ROS) scavengers and lipid peroxidation-inhibiting enzymes. The potential of ALDHs to interfere with H2O2 was also shown for recombinant bacterial proteins. [source]

Role of the cytoplasmic domain of the L1 cell adhesion molecule in brain development

THE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 7 2010
Yukiko Nakamura
Abstract Mutations in the human L1CAM gene cause X-linked hydrocephalus and MASA (Mental retardation, Aphasia, Shuffling gait, Adducted thumbs) syndrome. In vitro studies have shown that the L1 cytoplasmic domain (L1CD) is involved in L1 trafficking, neurite branching, signaling, and interactions with the cytoskeleton. L1cam knockout (L1KO) mice have hydrocephalus, a small cerebellum, hyperfasciculation of corticothalamic tracts, and abnormal peripheral nerves. To explore the function of the L1CD, we made three new mice lines in which different parts of the L1CD have been altered. In all mutant lines L1 protein is expressed and transported into the axon. Interestingly, these new L1CD mutant lines display normal brain morphology. However, the expression of L1 protein in the adult is dramatically reduced in the two L1CD mutant lines that lack the ankyrin-binding region and they show defects in motor function. Therefore, the L1CD is not responsible for the major defects observed in L1KO mice, yet it is required for continued L1 protein expression and motor function in the adult. J. Comp. Neurol. 518:1113,1132, 2010. © 2009 Wiley-Liss, Inc. [source]

OsRecQ1, a QDE-3 homologue in rice, is required for RNA silencing induced by particle bombardment for inverted repeat DNA, but not for double-stranded RNA

THE PLANT JOURNAL, Issue 2 2008
Hui Chen
Summary Based on the nucleotide sequence of QDE-3 in Neurospora crassa, which is involved in RNA silencing, rice (Oryza sativa) mutant lines disrupted by the insertion of the rice retrotransposonTos17 were selected. Homozygous individuals from the M1 and M2 generations were screened and used for further analyses. The expression of the gene was not detected in leaves or calli of the mutant lines, in contrast to the wild type (WT). Induction of RNA silencing by particle bombardment was performed to investigate any effects of the OsRecQ1 gene on RNA silencing with silencing inducers of the GFP (green fluorescence protein)/GUS (, -glucuronidase) gene in the mutant lines. The results showed that OsRecQ1 is required for RNA silencing induced by particle bombardment for inverted-repeat DNA, but not for double-stranded RNA (dsRNA). The levels of transcripts from inverted-repeat DNA were much lower in the mutant lines than those in the WT. Furthermore, no effects were observed in the accumulation of endogenous microRNAs (miR171 and miR156) and the production of the short interspersed nuclear element retroelement by small interfering RNA. On the basis of these results, we propose that OsRecQ1 may participate in the process that allows inverted repeat DNA to be transcribed into dsRNA, which can trigger RNA silencing. [source]

ATR and ATM play both distinct and additive roles in response to ionizing radiation

THE PLANT JOURNAL, Issue 6 2006
Kevin M. Culligan
Summary The ATR and ATM protein kinases are known to be involved in a wide variety of responses to DNA damage. The Arabidopsis thaliana genome includes both ATR and ATM orthologs, and plants with null alleles of these genes are viable. Arabidopsis atr and atm mutants display hypersensitivity to , -irradiation. To further characterize the roles of ATM and ATR in response to ionizing radiation, we performed a short-term global transcription analysis in wild-type and mutant lines. We found that hundreds of genes are upregulated in response to , -irradiation, and that the induction of virtually all of these genes is dependent on ATM, but not ATR. The transcript of CYCB1;1 is unique among the cyclin transcripts in being rapidly and powerfully upregulated in response to ionizing radiation, while other G2 -associated transcripts are suppressed. We found that both ATM and ATR contribute to the induction of a CYCB1;1:GUS fusion by IR, but only ATR is required for the persistence of this response. We propose that this upregulation of CYCB1;1 does not reflect the accumulation of cells in G2, but instead reflects a still unknown role for this cyclin in DNA damage response. [source]

Functionally redundant SHI family genes regulate Arabidopsis gynoecium development in a dose-dependent manner

THE PLANT JOURNAL, Issue 1 2006
Sandra Kuusk
Summary Gene duplication events, and the subsequent functional divergence of duplicates, are believed to be important evolutionary agents, driving morphological diversification. We have studied the structural and functional diversification of members of a plant-specific gene family in Arabidopsis thaliana by analysing mutant phenotypes, expression patterns and phylogeny. The SHI gene family comprises ten members that encode proteins with a RING finger-like zinc finger motif. We show that, despite being highly divergent in sequence, except in two conserved regions, many of the SHI -related genes are partially redundant in function and synergistically promote gynoecium, stamen and leaf development in Arabidopsis. Gynoecia of the loss-of-function sty1-1 mutant display subtle morphological defects, and, although mutations in the related STY2, SHI, SRS3, SRS4, SRS5, SRS7 and LRP1 genes have no apparent effect on gynoecium development, the sty1-1 mutant phenotype is gradually enhanced in double, triple, quadruple and quintuple mutant combinations, suggesting a remarkably extensive functional conservation within the family, which appears to be based on dosage dependency and protection against dominant negative mutations. In multiple mutant lines, all marginal tissues in the apical part of the gynoecium are dramatically reduced or missing, and our data indicate that SHI family members may promote formation of these tissues downstream of the transcriptional co-repressor LEUNIG (LUG). [source]

Plasma membrane NADH-oxidoreductase in cells carrying mitochondrial DNA G11778A mutation and in cells devoid of mitochondrial DNA (,0)

BIOFACTORS, Issue 4 2004
Safarina G. Malik
Abstract The mammalian plasma membrane (PM) NADH-oxidoreductase (PMOR) system is a multi-enzyme complex located in the plasma membrane of all eukaryotic cells, harboring at least two distinct activities, the plasma membrane NADH-ferricyanide reductase and the NADH-oxidase. To assess the behaviour of the two activities of the PMOR system, we measured the NADH-ferricyanide reductase and NADH-oxidase activities in fibroblast cell lines derived from patients carrying a mitochondrial DNA (mtDNA) G11778A mutation. We also measured the two activities in other cell lines, the HL-60 and HeLa (S3) lines, as well as in ,0 cells (cells devoid of mtDNA) generated from those lines and the fibroblast cells. These ,0 cells consequently lack oxidative phosphorylation and rely on anaerobic glycolysis for their ATP need. We have proposed that in ,0 cells, at least in part, up-regulation of the PMOR is a necessity to maintain the NAD+/NADH ratio, and a pre-requisite for cell growth and viability. We show here that the PM NADH-ferricyanide reductase activity was up-regulated in HL-AV2 (HL-60 ,0) cell lines, but not in the other ,0 and mtDNA mutant lines. The plasma membrane NADH oxidase activity was found to be up-regulated in both HL-AV2 and HeLa ,0 cell lines, but not significantly in the fibroblast ,0 and G11778A lines. [source]

4141: Visual phenotyping at the "Institut Clinique de la Souris"

ACTA OPHTHALMOLOGICA, Issue 2010
MJ ROUX
Purpose Visual diseases come in many flavors, with a large variety of affected tissues (eye anterior segment, retina, optic nerve, cortex ,), ages of onset, rate of progression and causal factors. In Western countries, if the majority of these diseases are now curable, millions of people are still affected by blindness or low vision, as many retinal diseases (age-related macular degeneration, retinitis pigmentosa, diabetic retinopathy, glaucoma,) still lack efficient treatments. In a facility devoted to mouse phenotyping as the Mouse Clinic Institute (MCI), it is thus of major importance to propose an efficient visual phenotyping platform, to pick up visual defects in screened mutants, to assess the beneficial effects of potential treatments or the eventual adverse effects of drugs targeting the CNS. Methods Methods: Mouse mutant lines from the Eumodic European project, as well as lines from specific academic projects, go through clinical observation (slit lamp, fundus imaging) in the context of a behavioral phenotyping pipeline, or are assessed in more details with angiography, optomotor response, electroretinography, retinal histology and/or immunohistochemistry. Results To illustrate the possibilities offered by the MCI visual phenotyping platform, we will present results obtained from various projects, as well as the validation of electroretinography protocols to follow dark adaptation and the effect of acute drug injections. Conclusion In an environment allowing for an in depth phenotyping, from behavior to biochemistry, metabolism and cardiology, the MCI visual phenotyping platform provides a comprehensive set of tests to get the most out of genetically modified mice. [source]

4142: The Sanger Mouse Genetics Programme: high throughput characterisation of knockout mice

4143: The German Mouse Clinic: recent findings from the Eye Screen

ACTA OPHTHALMOLOGICA, Issue 2010
O PUK
Purpose The purpose of this study was the large-scale screening of different mouse mutant lines in order to detect novel models for eye disorders. Methods The eyes of the mouse mutants were analyzed by slit lamp biomicroscopy, funduscopy, laser interference biometry, optokinetic drum, and histology. Results In the past 12 months, 46 mouse mutant lines were investigated in the primary Eye Screen of the German Mouse Clinic (GMC). These included Csemp1 and Aey69 that exhibited irregular eye development. All tested mice of the mutant line Csemp1 unexpectedly showed white fundus flecks and significantly reduced axial eye lengths. Moreover, we additionally found strong opacities in a least a portion of the Csemp1 mutant lenses. Aey69 mice are severely microphthalmic due to a yet undefined ENU-induced mutation. The rudimentary eyes completely lack ocular structures as iris or lens. Further significant irregularities in fat metabolism, immunology, and behaviour were detected in the GMC-wide primary screen. Linkage studies mapped the mutated site on chromosome 3 within a 0.78 Mb spanning region between the flanking microsatellite markers D3Mit188 and D3Mit76. Among the 34 positional candidate genes, Tnrc4 (elav-like family member 3) and Selenbp1 (selenium binding protein 1) are expressed in the eye. Sequencing studies in order to detect the causative mutation of Aey69 are in process. Conclusion Two novel mouse models for microphthalmia were detected in the primary Eye Screen of the GMC. These mutant lines will provide further insights into molecular mechanisms behind this kind of eye disease. [source]