Cloning, tissue expression pattern characterization and chromosome localization of human peptide methionine sulfoxide reductase cDNA

Oxidation and reduction of some amino acids are one of the molecular mechanisms for regulating the function of proteins. The oxidation of methionine (Met) to methionine sulfoxide (Met(O)) results in decreasing or loss of the biological activity of related proteins. It was found that peptide methionine sulfoxide reductase (msrA) can reduce Met(O) to Met and therefore restored the biological function of the oxidized proteins. To reveal the methionine oxidation-reduction mechanism in human body, in this study, the cDNA sequence of bovinemsrA was used as an information-probe to screen the human EST database. Based on a contig assembled from homologous ESTs, a 1 256-bp humanMSRA cDNA was cloned from several human cDNA libraries. The cDNA contains an open reading frame (ORF) of 705 bp in length, which encodes 235 amino acid residues. Homology comparison revealed that human MSRA shares 88% and 61% identities with bovine andEscherichia coli msrA protein respectively. Expression pattern analysis revealed a single 1.6-kb transcript of humanMSRA in most human tissues and with highest expression in kidney. By radiation hybrid parlel mapping, the gene was localized to human chromosome 8p22-23 between markers D8S518 and D8S550. There are 2 human inherited diseases Keratolytic Winter Erythema and Microcephaly related genes in this region, it is inferred that humanMSRA might be the candidate of the two diseases.