Isolation and mapping of the rabbit DM genes

Area of Science:

• Immunology
• Genetics
• Molecular Biology

Background:

• Peptide presentation by Major Histocompatibility Complex (MHC)-encoded class II antigens is critical for adaptive immunity.
• The MHC class II DM loci play a vital role in this antigen processing pathway.

Purpose of the Study:

• To identify and characterize the rabbit orthologues of human MHC class II DM genes (HLA-DMA and HLA-DMB).
• To investigate the evolutionary relationship of rabbit DM genes within the MHC class II family.

Main Methods:

• Identification of rabbit MHC DM genes (RLA-DMA and RLA-DMB) through sequence analysis.
• Comparative sequence analysis to determine evolutionary relationships with human and mouse DM genes.
• Mapping of the RLA-DM locus within the rabbit MHC region.

Main Results:

• Rabbit RLA-DMA and RLA-DMB genes were identified with significant sequence identity to human HLA-DMA (76.9%) and HLA-DMB (78.8%).
• Rabbit DM genes exhibit greater similarity to human HLA-DM than to mouse H2-DM.
• RLA-DM locus is located in the rabbit MHC class II region, flanked by DP and DOB loci.
• Variability was observed in the amino terminus of DMa chains and cytoplasmic tails of DMalpha and DMbeta chains.
• Rabbit DM genes are coexpressed with class II genes in lymphoid tissues.

Conclusions:

• The identified rabbit MHC class II DM genes are orthologues of human genes and are conserved in mammals.
• The DM family represents a distinct lineage within the MHC class II family, separate from bony fish class II genes.
• These findings contribute to understanding the evolution and function of MHC class II antigen presentation pathways.