Rhesus macaque MHC class I molecules show differential subcellular localizations (vol 62, pg 149, 2010)

The MHC class I gene family of rhesus macaques is characterised by considerable gene duplications. While a HLA-C-orthologous gene is absent, the Mamu-A and in particular the Mamu-B genes have expanded, giving rise to plastic haplotypes with differential gene content. Although some of the rhesus macaque MHC class I genes are known to be associated with susceptibility/resistance to infectious diseases, the functional significance of duplicated Mamu-A and Mamu-B genes and the expression pattern of their encoded proteins are largely unknown. Here, we present data of the subcellular localization of AcGFP-tagged Mamu-A and Mamu-B molecules. We found strong cell surface and low intracellular expression for Mamu-A1, Mamu-A2 and Mamu-A3-encoded molecules as well as for Mamu-B 01704, Mamu-B 02101, Mamu-B 04801, Mamu-B 06002 and Mamu-B 13401. In contrast, weak cell surface and strong intracellular expression was seen for Mamu-A4 1403, Mamu-B 01202, Mamu-B 02804, Mamu-B 03002, Mamu-B 05704, Mamu-I 010201 and Mamu-I 0121. The different expression patterns were assigned to the antigen-binding alpha 1 and alpha 2 domains, suggesting failure of peptide binding is responsible for retaining 'intracellular' Mamu class I molecules in the endoplasmic reticulum. These findings indicate a diverse functional role of the duplicated rhesus macaque MHC class I genes.