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Allele Expression (allele + expression)
Selected AbstractsB-F DNA sequence variability in Brazilian (blue-egg Caipira) chickensANIMAL GENETICS, Issue 4 2004C. A. V. Lima-Rosa Summary A total of 100 chickens from the Brazilian (blue-egg Caipira) native breed were studied in relation to exon 2 of the B-F genes of the major histocompatibility complex (MHC) region. After a first screening on 100 birds, 22 animals were selected for amplification, cloning and sequencing experiments of exons 2,4 (a total of 1048 bp) of their DNA. Twenty-three sequences were obtained, of which at least 10 appear novel. Inferred protein sequences were compared with those previously described, totalling 41 different sequences with amino acid changes in 33 of the 88 sites in ,1, and 34 of the 91 sites in ,2 domains. Allele expression was investigated in these animals through cloning experiments. The blue-egg Caipira chickens may provide a source of novel B-F alleles for genetic improvement programmes. [source] Generation and characterization of a novel neural crest marker allele, Inka1-LacZ, reveals a role for Inka1 in mouse neural tube closureDEVELOPMENTAL DYNAMICS, Issue 4 2010Bethany S. Reid Abstract Previous studies identified Inka1 as a gene regulated by AP-2, in the neural crest required for craniofacial morphogenesis in fish and frog. Here, we extend the analysis of Inka1 function and regulation to the mouse by generating a LacZ knock-in allele. Inka1-LacZ allele expression occurs in the cephalic mesenchyme, heart, and paraxial mesoderm prior to E8.5. Subsequently, expression is observed in the migratory neural crest cells and their derivatives. Consistent with expression of Inka1 in tissues of the developing head during neurulation, a low percentage of Inka1,/, mice show exencephaly while the remainder are viable and fertile. Further studies indicate that AP-2, is not required for Inka1 expression in the mouse, and suggest that there is no significant genetic interaction between these two factors during embryogenesis. Together, these data demonstrate that while the expression domain of Inka1 is conserved among vertebrates, its function and regulation are not. Developmental Dynamics 239:1188,1196, 2010. © 2010 Wiley-Liss, Inc. [source] Human leukocyte antigen,associated sequence polymorphisms in hepatitis C virus reveal reproducible immune responses and constraints on viral evolution,HEPATOLOGY, Issue 2 2007Joerg Timm CD8+ T cell responses play a key role in governing the outcome of hepatitis C virus (HCV) infection, and viral evolution enabling escape from these responses may contribute to the inability to resolve infection. To more comprehensively examine the extent of CD8 escape and adaptation of HCV to human leukocyte antigen (HLA) class I restricted immune pressures on a population level, we sequenced all non-structural proteins in a cohort of 70 chronic HCV genotype 1a-infected subjects (28 subjects with HCV monoinfection and 42 with HCV/human immunodeficiency virus [HIV] coinfection). Linking of sequence polymorphisms with HLA allele expression revealed numerous HLA-associated polymorphisms across the HCV proteome. Multiple associations resided within relatively conserved regions, highlighting attractive targets for vaccination. Additional mutations provided evidence of HLA-driven fixation of sequence polymorphisms, suggesting potential loss of some CD8 targets from the population. In a subgroup analysis of mono- and co-infected subjects some associations lost significance partly due to reduced power of the utilized statistics. A phylogenetic analysis of the data revealed the substantial influence of founder effects upon viral evolution and HLA associations, cautioning against simple statistical approaches to examine the influence of host genetics upon sequence evolution of highly variable pathogens. Conclusion: These data provide insight into the frequency and reproducibility of viral escape from CD8+ T cell responses in human HCV infection, and clarify the combined influence of multiple forces shaping the sequence diversity of HCV and other highly variable pathogens. (HEPATOLOGY 2007.) [source] MHC haplotype frequencies in a UK breeding colony of Mauritian cynomolgus macaques mirror those found in a distinct population from the same geographic originJOURNAL OF MEDICAL PRIMATOLOGY, Issue 1 2009Edward T. Mee Abstract Background, Mauritian cynomolgus macaques have greatly restricted genetic diversity in the MHC region compared to other non-human primates; however, the frequency of common MHC haplotypes among captive-bred populations has not been reported. Methods, Microsatellite PCR was used to determine MHC haplotype frequencies among captive macaques at a UK breeding facility. Allele-specific PCR and reference strand conformational analysis were used to determine the allele expression profile of a subset of animals. Results, Haplotypes H3 (21%) and H1 (19%) were most common in the captive population of Mauritian cynomolgus macaques. Predicted alleles were detected by allele-specific PCR-SSP in 98% of animals. Allele expression profiles were similar in animals with identical haplotypes. Conclusions, Mauritian cynomolgus macaques in the UK breeding facility have restricted MHC diversity comparable to a previously described population. Microsatellite-derived haplotypes are highly predictive of allele expression. A selective breeding program has been established to produce MHC-identical animals for biomedical research. [source] Changes in impact of HLA class I allele expression on HIV-1 plasma virus loads at a population level over timeMICROBIOLOGY AND IMMUNOLOGY, Issue 4 2010Michiko Koga ABSTRACT HLA class I allele types have differential impacts on the level of the pVL and outcome of HIV-1 infection. While accumulations of CTL escape mutations at population levels have been reported, their actual impact on the level of the pVL remains unknown. In this study HLA class I types from 141 untreated, chronically HIV-1 infected Japanese patients diagnosed from 1995,2007 were determined, and the associations between expression of individual HLA alleles and level of pVL analyzed. It was found that the Japanese population has an extremely narrow HLA distribution compared to other ethnic groups, which may facilitate accumulation of CTL escape mutations at the population level. Moreover while they uniquely lack the most protective HLA-B27/B57, they commonly express the alleles that are protective in Caucasians (A11:10.4%, A26:11.55%, B51:8.6% and Cw14:12.7%). Cross-sectional analyses revealed no significant associations between expression of individual alleles and the level of the pVL. The patients were then stratified by the date of HIV diagnosis and the analyses repeated. It was found that, before 2001, B51+ individuals displayed significantly lower pVL than the other patients (median: 5150 vs. 18 000 RNA copies/ml, P= 0.048); however thereafter this protective effect waned and disappeared, whereas no changes were observed for any other alleles over time. These results indicate that, at a population level, some HLA alleles have been losing their beneficial effects against HIV disease progression over time, thereby possibly posing a significant challenge for HIV vaccine development. However such detrimental effects may be limited to particular HLA class I alleles. [source] | |||||||||||||