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Organization of the origins of replication of the chromosomes of Mycobacterium smegmatis, Mycobacterium leprae and Mycobacterium tuberculosis and isolation of a functional origin from M. smegmatis
Author(s) -
Salazar Leirla,
Fsihi Hafida,
Rossi Edda,
Riccardi Giovanna,
Rios Carmen,
Cole Stewart T.,
Takiff Howard E.
Publication year - 1996
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1996.tb02617.x
Subject(s) - biology , dnaa , mycobacterium smegmatis , mycobacterium leprae , genetics , microbiology and biotechnology , mycobacterium tuberculosis , origin of replication , gene , dna replication , tuberculosis , leprosy , medicine , pathology , immunology
Summary The genus Mycobacterium is composed of species with widely differing growth rates ranging from approximately three hours in Mycobacterium smegmatis to two weeks in Mycobacterium leprae . As DNA replication is coupled to cell duplication, it may be regulated by common mechanisms. The chromosomal regions surrounding the origins of DNA replication from M. smegmatis, M. tuberculosis , and M. leprae have been sequenced, and show very few differences. The gene order, rnpA‐rpmH‐dnaA‐dnaN‐recF‐orf‐gyrB‐gyrA , is the same as in other Gram‐positive organisms. Although the general organization in M. smegmatis is very similar to that of Streptomyces spp., a closely related genus, M. tuberculosis and M. leprae differ as they lack an open reading frame, between dnaN and recF , which is similar to the gnd gene of Escherichia coli . Within the three mycobacterial species, there is extensive sequence conservation in the intergenic regions flanking dnaA , but more variation from the consensus DnaA box sequence was seen than in other bacteria. By means of subcloning experiments, the putative chromosomal origin of replication of M. smegmatis , containing the dnaA‐dnaN region, was shown to promote autonomous replication in M. smegmatis , unlike the corresponding regions from M. tuberculosis or M. leprae .