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Receptor Locus (receptor + locus)

Distribution by Scientific Domains
Life Sciences57%
Medical Sciences42%

Selected Abstracts

The dynamic TCR,: TCR, chains in the amphibian Xenopus tropicalis utilize antibody-like V genes

EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 8 2010
Zuly E. Parra
Abstract The content and organization of the Xenopus tropicalis TCR,/, locus was determined. This locus is highly conserved among tetrapods, with the genes encoding the TCR, chains embedded with those encoding TCR,. However, the frog TCR,/, is unusual in that it contains V genes that appear indistinguishable from those in the IgH locus (VH). These V genes, termed VH,, make up 70% of the V genes at the TCR, locus and are expressed exclusively in TCR, chains. Finding TCR, chains that use antibody-like V domains in frogs is similar to the situation in shark TCR, variants and TCR, in marsupials. These results suggest that such unconventional TCR may be more widespread across vertebrate lineages than originally thought and raise the possibility of previously unrealized subsets of T cells. We also revealed close linkage of TCR,/,, IgH, and Ig, in Xenopus which, in combination with linkage analyses in other species, is consistent with the previous models for the emergence of these antigen receptor loci. [source]

How to keep V(D)J recombination under control

IMMUNOLOGICAL REVIEWS, Issue 1 2004
Marjorie A. Oettinger
Summary:, Breaking apart chromosomes is not a matter to be taken lightly. The possible negative outcomes are obvious: loss of information, unstable chromosomes, chromosomal translocations, tumorigenesis, or cell death. Utilizing DNA rearrangement to generate the desired diversity in the antigen receptor loci is a risky business, and it must be carefully controlled. In general, the regulation is so precise that the negative consequences are minimal or not apparent. They are visible only when the process of V(D)J recombination goes awry, as for example in some chromosomal translocations associated with lymphoid tumors. Regulation is imposed not only to prevent the generation of random breaks in the DNA, but also to direct rearrangement to the appropriate locus or subregion of a locus in the appropriate cell at the appropriate time. Antigen receptor rearrangement is regulated essentially at four different levels: expression of the RAG1/2 recombinase, intrinsic biochemical properties of the recombinase and the cleavage reaction, the post-cleavage /DNA repair stage of the process, and accessibility of the substrate to the recombinase. Within each of these broad categories, multiple mechanisms are used to achieve the desired aims. The major focus of this review is on accessibility control and the role of chromatin and nuclear architecture in achieving this regulation, although other issues are touched upon. [source]

Spontaneously active and InsP3 -activated ion channels in cell nuclei from rat cerebellar Purkinje and granule neurones

THE JOURNAL OF PHYSIOLOGY, Issue 3 2005
Sergey M. Marchenko
Increases in Ca2+ concentration in the nucleus of neurones modulate gene transcription and may be involved in activity-dependent long-term plasticity, apoptosis, and neurotoxicity. Little is currently known about the regulation of Ca2+ in the nuclei of neurones. Investigation of neuronal nuclei is hampered by the cellular heterogeneity of the brain where neurones comprise no more than 10% of the cells. The situation is further complicated by large differences in properties of different neurones. Here we report a method for isolating nuclei from identified central neurones. We employed this technique to study nuclei from rat cerebellar Purkinje and granule neurones. Patch-clamp recording from the nuclear membrane of Purkinje neurones revealed numerous large-conductance channels selective for monovalent cations. The nuclear membrane of Purkinje neurones also contained multiple InsP3 - activated ion channels localized exclusively in the inner nuclear membrane with their receptor loci facing the nucleoplasm. In contrast, the nuclear membrane of granule neurones contained only a small number of mainly anion channels. Nuclear InsP3 receptors (InsP3Rs) were activated by InsP3 with EC50= 0.67 ,m and a Hill coefficient of 2.5. Ca2+ exhibited a biphasic effect on the receptors elevating its activity at low concentrations and inhibiting it at micromolar concentrations. InsP3 in saturating concentrations did not prevent the inhibitory effect of Ca2+, but strongly increased InsP3R activity at resting Ca2+ concentrations. These data are the first evidence for the presence of intranuclear sources of Ca2+ in neurones. Ca2+ release from the nuclear envelope may amplify Ca2+ transients penetrating the nucleus from the cytoplasm or generate Ca2+ transients in the nucleus independently of the cytoplasm. [source]

No linkage of the interleukin-4 receptor locus on chromosome 16p11.2-12.1 with sarcoidosis in German multiplex families

INTERNATIONAL JOURNAL OF IMMUNOGENETICS, Issue 3 2002
A. Bohnert
Summary We typed 241 members of 62 sarcoidosis families with 136 affected siblings for three single nucleotide polymorphisms of the interleukin-4 receptor alpha-chain gene (IL4R). Allele frequencies in patients were compared to those of healthy unrelated control individuals. The segregation of the three-point IL4R haplotypes completed by two flanking highly polymorphic microsatellite polymorphisms revealed no evidence for linkage of the IL4R gene locus with sarcoidosis. [source]

Refined localization of the Escherichia coli F4ab/F4ac receptor locus on pig chromosome 13

ANIMAL GENETICS, Issue 5 2009
D. Joller
Summary Diarrhoea in newborn and weaned pigs caused by enterotoxigenic Escherichia coli (ETEC) expressing F4 fimbriae leads to considerable losses in pig production. In this study, we refined the mapping of the receptor locus for ETEC F4ab/F4ac adhesion (F4bcR) by joint analysis of Nordic and Swiss data. A total of 236 pigs from a Nordic experimental herd, 331 pigs from a Swiss experimental herd and 143 pigs from the Swiss performing station were used for linkage analysis. Genotyping data of six known microsatellite markers, two newly developed markers (MUC4gt and HSA125gt) and an intronic SNP in MUC4 (MUC4-8227) were used to create the linkage map. The region for F4bcR was refined to the interval SW207,S0075 on pig chromosome 13. The most probable position of F4bcR was in the SW207,MUC4 region. The order of six markers was supported by physical mapping on the BAC fingerprint contig from the Wellcome Trust Sanger Institute. Thus, the region for F4bcR could be reduced from 26 to 14 Mb. [source]

The g.243A>G mutation in intron 17 of MUC4 is significantly associated with susceptibility/resistance to ETEC F4ab/ac infection in pigs

ANIMAL GENETICS, Issue 4 2007
Q.-L. Peng
Summary Using a porcine radiation hybrid panel, we assigned the mucin 4 (MUC4) gene to SSC13q41, which harbours the enterotoxigenic Escherichia coli (ETEC) F4ab/ac receptor locus. In addition, we identified two SNPs in intron 17 of MUC4 (DQ124298:g.243A>G and DQ124298:g.334A>G) in the parental population of a White Duroc × Erhualian cross. Association analysis showed that the MUC4 g.243A>G mutation was strongly associated with ETEC F4ab/ac, and especially with F4ac adhesion phenotypes in the White Duroc × Erhualian resource population, indicating that this polymorphism was in a significant linkage disequlibrium with the ETEC F4ab/ac receptor locus. Because of different linkage disequlibrium values between the ETEC F4ab and F4ac adhesion phenotypes and the MUC4 g.243A>G mutation, we argue that the inheritance of F4ab and F4ac receptors might be under the control of two closely linked loci. [source]