KatF (sigma S) synthesis in Escherichia coli is subject to posttranscriptional regulation.

A transcriptional fusion of katF to the lacZ gene was expressed at increasingly higher levels throughout the exponential phase, but a translational fusion was expressed at low levels during exponential-phase growth and was induced 160-fold during the transition to stationary phase, implicating a posttranscriptional mechanism in the regulation of KatF synthesis. Mutational analyses suggested that the initiation codon of katF is the second ATG in the previously identified open reading frame.