PUTATIVE FUNCTIONAL DOMAIN WITHIN ORF2 ON THE MYCOBACTERIUM INSERTIONSEQUENCES IS900 AND IS902

Repeated DNA sequences have been identified in a range of mycobacteria l species and have been implicated in the increased virulence of some of these species, namely, Mycobacterium paratuberculosis and M. avium subsp. silvaticum. Here we present a case to suggest that the insertio n sequences IS900 and IS902 encode a protein from a putative gene posi tioned on the complementary strand to their transposase genes. Based o n amino acid homology analyses, this open reading frame (ORF2) could e ncode a transport protein. The ORF2 protein thus IS900 and IS902, may have a role in the increased pathogenicity of M. paratuberculosis and M. avium subsp. silvaticum from an M. avium background.