GENE ARRANGEMENT AND ORGANIZATION IN A SIMILAR-TO 76 KB FRAGMENT ENCOMPASSING THE ORIC REGION OF THE CHROMOSOME OF MYCOBACTERIUM-LEPRAE

A continuous 75 627 bp segment of the Mycobacterium leprae chromosome spanning the oriC region was sequenced. The gene order at this locus w as similar to that found in the replication origin region of many othe r prokaryotes, particularly Mycobacterium tuberculosis and Streptomyce s coelicolor. As in the case of several Cram-positive bacteria, essent ial genes involved in basic cellular functions, such as DNA or RNA met abolism (dnaA, dnaB dnaN, gyrB, gyrA, pcnB, recF, rnpA, ssb), cell wal l synthesis (ponA, pbpA) and probably cell division (gidB, rodA) were found. Strikingly, the gidA gene was absent from this part of the geno me and there was no rRNA operon near oriC. The gyrA gene harbours an i ntein coding sequence indicating that protein splicing is required to produce the mature A subunit of DNA gyrase. Among the many other notew orthy features were ORFs encoding putative serine/threonine protein ki nases and a protein phosphatase, three tRNA genes, one M. leprae-speci fic repetitive element and a glnQ pseudogene.