Phylogenetic Distribution of CMP-Neu5Ac Hydroxylase (CMAH), the Enzyme Synthetizing the Proinflammatory Human Xenoantigen Neu5Gc

Peri, Sateesh; Kulkarni, Asmita; Feyertag, Felix; Berninsone, Patricia M; Alvarez-Ponce, David

The presence of inactive CMAH sequences, and the absence of Neu5Gc, was also reported in a number of New World monkeys, indicating that CMAH pseudogenized in an ancestor of New World monkeys (Springer et al. 2014) . In agreement with these findings, we found a deletion spanning coding exons 3-15 in all available New World monkey genomes, including those of Saimiri boliviensis boliviensis (Bolivian squirrel monkey), Cebus capucinus (white-faced sapajou), Callithrix jacchus (marmoset), and Aotus nancymaae (Nancy Ma's night monkey). Ng et al. (2014) investigated the ferret genome and performed PCR analyses on another 14 species of musteloids and 2 species of pinnipeds. In all species investigated, they found a large deletion of nine protein-coding exons in the CMAH gene, suggesting a pseudogenization event in a common ancestor of musteloids and pinnipeds. In agreement with this hypothesis, we found no putatively functional CMAH genes in any of the musteloid and pinniped species investigated: The ferret (Mustela putorius furo) genome contains a disrupted CMAH gene, and the genomes of the Weddell seal (Leptonychotes weddellii) and the walrus (Odobenus rosmarus divergens) lack CMAH homologs.