Cloning and characterization of MHC-DQA1 and MHC-DQA2 molecules from yak (&amp;lt;i&amp;gt;Bos grunniens&amp;lt;/i&amp;gt;)

Fei Ge,Liping Wang,Sehroon Khan,Jing Leng,Xiangying Liu,Guozhi Li,Weidong Deng,Dongmei Xi,Sameeullah Memon,Shijun Li

doi:10.5194/aab-59-395-2016

Abstract

Abstract. The major histocompatibility complex (MHC) plays a crucial role in the processing and presentation of antigens and in discrimination between self and non-self. The aim of this investigation was to scrutinize the structural diversity and possible duplication of the MHC-DQA genes in yak (Bos grunniens). Two cDNA sequences were amplified and designated as Bogr-DQA1 (DQA*0101) and Bogr-DQA2 (DQA*2001) with GenBank accession numbers JQ864314 and JQ864315, respectively. The nucleotide and amino acid sequence alignment between Bogr-DQA1 and Bogr-DQA2 molecules showed that these two identified MHC-DQA gene sequences had more similarity to alleles of specific DQA1 and DQA2 genes from other Ruminantia species than to each other. The result from phylogenic investigation also revealed that there was a larger genetic distance between these two genes than between homologous genes from different species. The presence of different bovine DQA putative motifs and the large genetic distance between Bogr-DQA1 and Bogr-DQA2 suggest that these sequences are non-allelic. Further, these results indicate that DQA gene duplication occurs in ruminants. This study will be helpful in knowing MHC diversity in common ruminants and will deepen our understanding of the variation of immunological functions, evolutionary constraints, and selective forces that affect MHC variation within and between species.

Highlights

The extent of genetic diversity is known to be linked to the ability for adapting to environmental changes and with the capacity to evolve (Reed and Frankham, 2003)
The cDNA sequence analysis showed that the two genes are not homologous to any of the known yak genes
Both the sequences were deposited into the NCBI GenBank database with accession numbers JQ864314 and JQ864315 as well as the Immuno Polymorphism Database with assigned official names Bogr-DQA∗0101 and DQA∗2001, respectively, based on identity to existing bovine leukocyte antigen (BoLA)-DQA sequences

Summary

Introduction

The extent of genetic diversity is known to be linked to the ability for adapting to environmental changes and with the capacity to evolve (Reed and Frankham, 2003). The potential of an organism for evolutionary interactions with either pathogens or other species as well as its Darwinian fitness is related to immunological functions (Lazzaro and Little, 2009). Diversity of genes important for immune functions may be associated with resistance or susceptibility to pathogens (Trowsdale and Parham, 2004; Tibayrenc, 2007). A cluster of associated genes called the major histocompatibility complex (MHC) play a key role in presenting antigenic peptides to T lymphocytes (Klein, 1986). The class II genes of MHC encode for the α and β chains of DR and DQ dimer molecules, which present antigenic peptides to helper T cells (McKinney et al, 2013).

Methods

Results

Conclusion