The Mycobacterium marinum G13 promoter is a strong sigma 70-like promoter that is expressed in Escherichia coli and mycobacteria species

A Mycobacterium marinum promoter, designated G13, was isolated from a promoter-trap library as a constitutive producer of the mutant green fluorescent protein. Sequence analysis, primer extension analysis, and computer promoter prediction analysis indicate that the G13 promoter is very similar to Escherichia coli consensus sigma 70 promoters. Expression of the green fluorescent protein from the G13 promoter in M. marinum is, however, up to 40 times higher than that seen from the mycobacterial hsp60 promoter during exponential growth. Further, expression from this promoter does not appear to affect the growth of the organism in culture media or in macrophages. The strong expression of the G13 promoter allows it to be developed as a useful molecular tool for high level expression of markers in vitro.