A comprehensive mapping of the structure and gene organisation in the sheep MHC class I region

BMC Genomics

Research Article

MJ Stear¹  DM Groth²  EF Morgan²  N. Siva Subramaniam²  JD Wetherall² 

[1] Department of Animal Production and Public Health, Faculty of Veterinary Medicine, University of Glasgow, Bearsden Road, G61 1QH, Glasgow, UK;Institute of Biodiversity, Animal Health and Comparative Medicine, Garscube Estate, University of Glasgow, Bearsden Road, G61 1QH, Glasgow, UK;School of Biomedical Sciences, CHIRI Biosciences Research Precinct, Faculty of Health Sciences, Curtin University, GPO Box U1987, 6845, Perth, WA, Australia;

关键词: Major histocompatibility complex (MHC);    MHC class I;    Sheep;    Mapping;   

DOI  :  10.1186/s12864-015-1992-4

 received in 2015-04-24, accepted in 2015-10-06,  发布年份 2015

来源: Springer

【 摘 要 】

BackgroundThe major histocompatibility complex (MHC) is a chromosomal region that regulates immune responsiveness in vertebrates. This region is one of the most important for disease resistance because it has been associated with resistance or susceptibility to a wide variety of diseases and because the MHC often accounts for more of the variance than other loci. Selective breeding for disease resistance is becoming increasingly common in livestock industries, and it is important to determine how this will influence MHC polymorphism and resistance to diseases that are not targeted for selection. However, in sheep the order and sequence of the protein coding genes is controversial. Yet this information is needed to determine precisely how the MHC influences resistance and susceptibility to disease.MethodsCHORI bacterial artificial chromosomes (BACs) known to contain sequences from the sheep MHC class I region were sub-cloned, and the clones partially sequenced. The resulting sequences were analysed and re-assembled to identify gene content and organisation within each BAC. The low resolution MHC class I physical map was then compared to the cattle reference genome, the Chinese Merino sheep MHC map published by Gao, et al. (2010) and the recently available sheep reference genome.ResultsImmune related class I genes are clustered into 3 blocks; beta, kappa and a novel block not previously identified in other organisms. The revised map is more similar to Bovidae maps than the previous sheep maps and also includes several genes previously not annotated in the Chinese Merino BAC assembly and others not currently annotated in the sheep reference chromosome 20. In particular, the organisation of nonclassical MHC class I genes is similar to that present in the cattle MHC. Sequence analysis and prediction of amino acid sequences of MHC class I classical and nonclassical genes was performed and it was observed that the map contained one classical and eight nonclassical genes together with three possible pseudogenes.ConclusionsThe comprehensive physical map of the sheep MHC class I region enhances our understanding of the genetic architecture of the class I MHC region in sheep and will facilitate future studies of MHC function.

【 授权许可】

CC BY   
© Siva Subramaniam et al. 2015