Post-transcriptional control of a sporulation regulatory gene encoding transcription factor sigma H in Bacillus subtilis.
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.
Healy
J
J
Department of Cellular and Developmental Biology, Harvard University, Cambridge, Massachusetts 02138.
Weir
J
J
Smith
I
I
Losick
R
R
D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001412:Bacillus subtilis / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D015153:Blotting, Western; D003001:Cloning, Molecular; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005809:Genes, Regulator; D007158:Immunologic Techniques; D007700:Kinetics; D011401:Promoter Regions, Genetic; D012808:Sigma Factor / Q000302:isolation & purification / Q000378:metabolism*; D013171:Spores, Bacterial / Q000235:genetics; D014158:Transcription, Genetic; D001616:beta-Galactosidase / Q000235:genetics
D000900:Anti-Bacterial Agents; D012808:Sigma Factor; C012182:angustmycin A; D001616:beta-Galactosidase; D000241:Adenosine