The Major Histocompatibility Complex of Old World Camels-A Synopsis.

Plasil Plasil,Oppelt Oppelt,Wijkmark Wijkmark,Elbers Elbers,Horin Horin,Burger Burger

doi:10.3390/cells8101200

Abstract

This study brings new information on major histocompatibility complex (MHC) class III sub-region genes in Old World camels and integrates current knowledge of the MHC region into a comprehensive overview for Old World camels. Out of the MHC class III genes characterized, TNFA and the LY6 gene family showed high levels of conservation, characteristic for MHC class III loci in general. For comparison, an MHC class II gene TAP1, not coding for antigen presenting molecules but functionally related to MHC antigen presenting functions was studied. TAP1 had many SNPs, even higher than the MHC class I and II genes encoding antigen presenting molecules. Based on this knowledge and using new camel genomic resources, we constructed an improved genomic map of the entire MHC region of Old World camels. The MHC class III sub-region shows a standard organization similar to that of pig or cattle. The overall genomic structure of the camel MHC is more similar to pig MHC than to cattle MHC. This conclusion is supported by differences in the organization of the MHC class II sub-region, absence of functional DY genes, different organization of MIC genes in the MHC class I sub-region, and generally closer evolutionary relationships of camel and porcine MHC gene sequences analyzed so far.

Highlights

The major histocompatibility complex (MHC) is a genomic region of critical importance for vertebrate immune functions
Bactrian camel samples were collected at three different locations in Mongolia and one sample was collected from a breeder in Austria, while dromedary samples were from Jordan, Saudi Arabia, UAE, Qatar, Sudan, Kenya, Kazakhstan and Nigeria
Compared to the available annotated coding sequences (CDSs) of Old World camels (XM_010994582.1:25-2265), one substitution was found in the CDS of the TAP1 gene

Summary

Introduction

The major histocompatibility complex (MHC) is a genomic region of critical importance for vertebrate immune functions. Different MHC molecules encoded by different alleles of multiple MHC genes can bind and present different groups of structurally similar antigenic oligopeptides. Compared to highly specific T- and B-cell receptors, MHC molecules are less specific. This phenomenon allows MHC molecules to cope with the immense diversity of protein antigens based on inherited genetic variation. Different antigen presenting molecules are encoded by different allelic variants of MHC class I and class II genes. The MHC region is characterized by many loci with immune as well as with non-immune functions. Multiple loci code for antigen presenting molecules that possess many alleles and have higher heterozygosity typically than

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