MYCOBACTERIUM-XENOPI IS1395, A NOVEL INSERTION-SEQUENCE EXPANDING THEIS256 FAMILY

An insertion sequence (IS) of Mycobacterium xenopi has been isolated a nd sequenced. This 1323 bp element, designated IS1395, is present in u p to 18 copies in the M. xenopi genome and may be harboured in an M. x enopi extrachromosomal element. It encodes a putative transposase of 4 15 amino acids which displays sequence homology to the Staphylococcus aureus IS256 family. Members of this class of elements have been descr ibed in the genus Mycobacterium - for example IS1081 is present in the M. tuberculosis complex, IS1245-IS1311 in M. avium, and IS6120 in M. smegmatis; these elements exhibit an 89 %, 45 % and 16 % amino acid id entity with IS1395, respectively Investigation of the host range of IS 1395 by Southern blot analysis revealed additional IS1395-related repe ated sequences in M. gordonae and M. celatum. Moreover, IS1395 represe nts a useful epidemiological tool for M. xenopi strain typing as it pr ovides a diversity of restriction fragment length polymorphism pattern s.