The number and organization of the rRNA genes of several strains of Mycobacterium simiae

The type strain of Mycobacterium simiae and four Cuban strains, each representing a group of variants sharing a characteristic pattern of glycopeptidolipids, were investigated. Each of the five strains was found to have a single rRNA ( rrn) operon per genome. Each rrn operon was found to be located downstream from murA. Unusually for slow-growing mycobacteria, three transcription start points were identified for each operon. Gene sequences were established extending from near to the 3′-ends of murA, the intergenic regions and the 5′-ends of the 16S rDNAs. Characteristic strain differences were identified.