Characterization of the regulatory mechanism of the virulence associated mce operons from Mycobacterium tuberculosis.

KLEPP, L; SANTANGELO, MP; CATALDI, A; BIGI, F

Iguazu, Misiones

Congreso; XL Reunión anual de la Sociedad Argentina de Investigaciones Bioquímicas y de Biología Molecular; 2004

Sociedad Argentina de Investigaciones Bioquímicas

The analysis of M tuberculosis genome revealed the existence of four homologous operons containing eight genes very similarly organized (mce1, mce2, mce3 and mce4). We have recently demonstrated that mutant strains of mce1, mce2 and mce3 operons have a reduced ability to multiply/persist in mammalian host when inoculated in mice, strongly suggesting that these operons are involved in M. tuberculosis virulence.  At least two regulator genes are involved in mce expression in M. tuberculosis. Our group has found that a transcriptional regulator, called mce3R, down regulates mce3 operon during the in vitro growing of M. tuberculosis. In this work we described the construction of a knockout M. tuberculosis strain in mce3R gene, obtained by allelic replacement. The expression profile of mce genes in this mutant strain was analysed by Western blotting using specific antibodies and the results were compared with those obtained for the wild type strain.