Physical mapping of Mycobacterium bovis BCG Pasteur reveals differences from the genome map of Mycobacterium tuberculosis H37Rv and from M. bovis

1 Unité de Génétique Moléculaire Bactérienne, Institut Pasteur, 28 rue du Docteur Roux, 75724 Paris Cedex 15, France 2 Unité de Génétique Mycobactérienne, Institut Pasteur, 28 rue du Docteur Roux, 75724 Paris Cedex 15, France 3 Laboratoire du BCG, Institut Pasteur, 28 rue du Docteur Roux, 75724 Paris Cedex 15, France ABSTRACT A Dral restriction map of the ~ 4.35 Mb circular chromosome of the vaccine strain Mycobacterium bovis BCG Pasteur was constructed by linking all 21 Dral fragments, ranging in size from 6 to 820 kb, using specific clones that spanned the Dral recognition sites as hybridization probes. The positions of 20 known genes were also established. Comparison of the resultant genome map with that of the virulent tubercle bacillus Mycobacterium tuberculosis H37Rv revealed extensive global conservation of the genomes of these two members of the M. tuberculosis complex. Possible sites of evolutionary rearrangements were localized on the chromosome of M. bovis BCG Pasteur by comparing the Asnl restriction profile with that of M. tuberculosis H37Rv. When selected cosmids from the corresponding areas of the genome of M. tuberculosis H37Rv were used as hybridization probes to examine different BCG strains, wild-type M. bovis and M. tuberculosis H37Rv, a number of deletions up to 10 kb in size, insertions and other polymorphisms were detected. In addition to the known deletions covering the genes for the protein antigens ESAT-6 and mpt64, other genetic loci exhibiting polymorphisms or rearrangements were detected in M. bovis BCG Pasteur. 4 Author for correspondence: Stewart T. Cole. Tel: +33 1 45688446. Fax: +33 1 40613583. e-mail: stcole@pasteur.fr Keywords: Mycobacterium bovis BCG Pasteur, tuberculosis, BCG vaccine, genomics Present address: INSERM U 411, Faculté Necker, 156 rue de Vaugirard, 75730 Paris Cedex 15, France. Present address: Institute of Medical Microbiology, University of Berne, 3010 Berne, Switzerland.