Open AccessExpression of Mycobacterium tuberculosis Rv1991c using an arabinose‐inducible promoter demonstrates its role as a toxin
Author(s) -
Carroll Paul,
Brown Amanda C.,
Hartridge Anna R.,
Parish Tanya
Publication year - 2007
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2007.00842.x
Subject(s) - mycobacterium smegmatis , antitoxin , biology , escherichia coli , gene , toxin , heterologous expression , microbiology and biotechnology , reporter gene , gene expression , heterologous , mycobacterium tuberculosis , genetics , recombinant dna , tuberculosis , medicine , pathology
Conditional gene expression systems are useful tools for studying the role of essential or toxic gene products in bacterial systems. There is a paucity of such systems available for use in the mycobacteria. The utility of the Escherichia coli arabinose‐inducible system was looked into, since it is tightly controlled in response to the presence of arabinose and glucose. It was demonstrated that the P BAD promoter can be used to express heterologous genes in Mycobacterium smegmatis . Expression of a lacZ reporter gene demonstrated that promoter activity was inducible in response to the presence of glucose, but only on solid medium. This system was utilized to study the functional consequences of expressing one member of a putative toxin–antitoxin pair (Rv1991c). Rv1991c has homology with a number of bacterial toxins, including ChpK, MazF and PemK. A potential antitoxin gene has been identified, adjacent to Rv1991c in the genome, which was coexpressed with the toxin. Expression of the toxin alone inhibited the growth of E. coli , whereas coexpression with the antitoxin did not. Expression of Rv1991c also led to a marked reduction of cell viability in M. smegmatis , confirming its role as a potent toxin.