Expression of the major porin gene mspA is regulated in Mycobacterium smegmatis.

ABSTRACT: MspA is the major porin of Mycobacterium smegmatis and is important for diffusion of small and hydrophilic solutes across its unique outer membrane. The start point of transcription of the mspA gene was mapped by primer extension and S1 nuclease experiments. The main promoter driving transcription of mspA was identified by single point mutations in lacZ fusions and resembled sigma(A) promoters of M. smegmatis. However, a 500-bp upstream fragment including P(mspA) in a transcriptional fusion with lacZ yielded only low beta-galactosidase activity, whereas activity increased 12-fold with a 700-bp fragment. Activation of P(mspA) by the 200-bp element was almost eliminated by increasing the distance by 14 bp, indicating binding of an activator protein. The chromosomal mspA transcript had a size

SUBMITTER: Hillmann D 

PROVIDER: S-EPMC1797333 | biostudies-literature | 2007 Feb

REPOSITORIES: biostudies-literature