Post‐transcriptional control of a sporulation regulatory gene encoding transcription factor σ^H in Bacillus subtilis

Abstract

The transcriptional regulatory gene spoOH encodes an RNA polymerase sigma factor called sigma H that directs gene expression at an early stage of sporulation in the Gram-positive bacterium Bacillus subtilis. We now report that conditions that induce sporulation cause a rapid increase in the cellular concentration of sigma H. This increase could account for the stimulated transcription of certain sigma H-controlled genes at the onset of sporulation. Experiments in which the expression of spoOH was monitored by use of a spoOH-lacZ fusion and in which expression of spoOH was artificially manipulated by use of an isopropyl-beta-D-thiogalacto-side-inducible promoter indicate that sporulation-induced increases in the amount of sigma H are not controlled at the level of the transcription of its structural gene. Rather, we infer the existence of post-transcriptional control mechanisms that govern sigma H levels, and we present evidence suggesting that increases in the amount of sigma H at the start of sporulation are due to increased translation or stability of the spoOH mRNA and, to a lesser extent, decreased turnover of spoOH protein.

Broadly heterogeneous activation of the master regulator for sporulation in Bacillus subtilis

“…2A and Fig. S2), indicating that accumulation of σ H at hour 0 is controlled at a posttranscriptional level, as noted previously (14,15). It therefore remained possible that σ H is rate limiting for 0A synthesis and that the increase in σ H contributes to the timing of induction of 0A synthesis.…”

Temporal and selective association of multiple sigma factors with RNA polymerase during sporulation in Bacillus subtilis

“…However, the evidence exists that the activity of s H is controlled by a feedback loop involving s A and s H (Fujita & Sadaie 1998b). There is also evidence that the activity of s H is controlled at the post-transcriptional and/or post-translational level (Healy et al 1991;Asai et al 1995;Stragier & Losick 1996). Therefore, an alternative explanation for the increased expression levels of s H -controlled genes when s A levels were reduced (Hicks & Grossman 1996) (Lord et al 1999).…”

Feedback control of morphogenesis in fungi by aromatic alcohols

“…Quorumsensing and nutrition-sensing pathways are also interconnected in bacteria (Lazazzera 2000). For example, in the Gram-positive bacterium Bacillus subtilis, the production of competence and sporulation factor (CSF), a quorum-sensing peptide, is regulated by starvation through a specific promoter recognition subunit of RNA polymerase, H , which is activated by starvation and the entry into stationary phase (Healy et al 1991;Lazazzera et al 1999). In many Gram-negative bacteria, such as Pseudomonas aeruginosa and Ralstonia solanacearum, the production of AHL depends on S , an RNA polymerase factor activated by starvation conditions (Flavier et al 1998;You et al 1998).…”