The regulatory elements of the Mycobacterium tuberculosis gene Rv3881c function efficiently in Escherichia coli.

We report efficient expression of the Mycobacterium tuberculosis gene Rv3881c in Escherichia coli from its M. tuberculosis promoter, attributable to an E. coli consensus Pribnow box and ribosome binding site. The N-terminal sequence of the recombinant E. coli-generated protein was identical to the predicted open reading frame of Rv3881c and transcription of the Rv3881c gene initiated at the same nucleotide position in both bacteria. We demonstrate the utility of this promoter for rapid analysis of expression in E. coli of heterologous gene constructs, for subsequent expression from the genomes of slow-growing mycobacteria such as Mycobacterium bovis-BCG. M. tuberculosis Rv3881c homologues were present in other pathogenic mycobacteria such as M. bovis-BCG, Mycobacterium szulgai and Mycobacterium kansasii.