Siddle Hannah V, Deakin Janine E, Baker Michelle L, Miller Robert D, Belov Katherine
Centre for Advanced Technologies in Animal Genetics and Reproduction, Faculty of Veterinary Science, University of Sydney, Sydney, Australia.
Immunogenetics. 2006 Jun;58(5-6):487-93. doi: 10.1007/s00251-006-0107-4. Epub 2006 Mar 28.
The major histocompatibility complex (MHC) plays an essential role in the adaptive immune system of vertebrates through antigen recognition. Although MHC genes are found in all vertebrates, the MHC region is dynamic and has changed throughout vertebrate evolution, making it an important tool for comparative genomics. Marsupials occupy an important position in mammalian phylogeny, yet the MHC of few marsupials has been studied in detail. We report the isolation and analysis of expressed MHC Class I genes from the tammar wallaby, a model marsupial used extensively for the study of mammalian reproduction, genetics, and immunology. We determined that there are at least 11 Class I loci in the tammar genome and isolated six expressed Class I sequences from spleen and testes cDNA libraries, representing at least four loci. Two of the Class I sequences contain substitutions at sites known to be important for antigen binding, perhaps impacting their ability to bind peptides, or the types of peptide to which they bind. Phylogenetic analysis of tammar wallaby Class I sequences and other mammalian Class I sequences suggests that some tammar wallaby and red-necked wallaby loci evolved from common ancestral genes.
主要组织相容性复合体（MHC）通过抗原识别在脊椎动物的适应性免疫系统中发挥着至关重要的作用。尽管在所有脊椎动物中都能发现MHC基因，但MHC区域是动态的，并且在整个脊椎动物进化过程中发生了变化，这使其成为比较基因组学的重要工具。有袋类动物在哺乳动物系统发育中占据重要地位，然而，对少数有袋类动物的MHC的研究还不够详细。我们报告了从帚尾袋鼩（一种广泛用于研究哺乳动物繁殖、遗传学和免疫学的有袋类动物模型）中分离和分析表达的MHC I类基因。我们确定帚尾袋鼩基因组中至少有11个I类基因座，并从脾脏和睾丸cDNA文库中分离出6个表达的I类序列，代表至少4个基因座。其中两个I类序列在已知对抗原结合很重要的位点上存在替换，这可能会影响它们结合肽的能力，或者它们所结合的肽的类型。对帚尾袋鼩I类序列和其他哺乳动物I类序列的系统发育分析表明，一些帚尾袋鼩和赤颈袋鼩的基因座是从共同的祖先基因进化而来的。
