Spx, a versatile regulator of the Bacillus subtilis stress response.

Spx is a central regulator of the Bacillus subtilis stress response. By binding to the alpha subunits of RNA polymerase, it regulates the expression of many stress response genes, while concurrently interfering with various developmental processes. The recent observation that Spx also represses transcription of ribosomal RNA adds a direct link between stress response and the control of translation in B. subtilis. Here, we discuss the significance of the regulation of translation and the transcription of translation-related genes during the bacterial stress response and the role of Spx in this process. Furthermore, we compare Spx with the role of DksA during stress response in proteobacteria.