ISOLATION BY GENETIC LABELING OF A NEW MYCOBACTERIAL PLASMID, PJAZ38,FROM MYCOBACTERIUM-FORTUITUM

In a two-step mating experiment with recipient strains of Mycobacteriu m smegmatis, the Mycobacterium fortuitum cryptic plasmid pJAZ38 was is olated. Plasmid pJAZ38 was genetically labeled by cointegration format ion mediated by the kanamycin-resistant mycobacterial transposon Tn611 . The region responsible for replication of pJAZ38, was located and se quenced. This region showed homology with the Mycobacterium avium plas mid pLR7 and the Mycobacterium scrofulaceum plasmid pMSC262, a family of plasmids which have been found to be widespread throughout the myco bacteria. Further experiments showed pJAZ38 to be stably inherited in the absence of selection pressure and compatible with the most commonl y used mycobacterial replicon, pAL5000. In contrast to pLR7 and pMSC26 2, pJAZ38 was able to replicate in M. smegmatis mc(2)155, making it a useful tool for mycobacterial genetics.