Sigma(s)-dependent regulation of yehZYXW, which encodes a putative osmoprotectant ABC transporter of Escherichia coli.

The Escherichia coli yehZYXW operon encodes a putative osmoprotectant uptake system of the ABC transporter family. yehZ is identical to osmF, an osmotically inducible gene identified previously. Construction and analysis of a yehZ-lacZ transcriptional fusion demonstrated that yehZ is inducible not only by osmolarity, but also upon entry into stationary phase. The osmotic and growth-phase regulations operate at a unique promoter, yehZp, and are totally dependent on the stress specific sigma factor sigma(s). The yehZYXW encoded ABC transporter appears as an additional element of the global stress response controlled by sigma(s).