Transcriptional control of the Bacillus subtilis spoIID gene

Abstract

We cloned the wild-type allele of the spolID locus of Bacillus subtilis. This DNA region was shown to be transcribed beginning within an hour after the onset of sporulation. The amount of spoIID mRNA present in ceUs at 1 h after the end of growth was more than 50-fold greater than it was in growing cells; the pool of this mRNA decreased steadily after 1.5 h after the end of growth. spoIlD mRNA was present in stationary-phase cells of sporulation mutants with lesions in the spoOJ and spolIB genes but was absent in cells carrying spoOB, spoOH, spoIA, spollE, spoliG, or spollIA mutations. In vitro runoff transcription with the Ef55, Ec37, Ea32, and Eu29 forms of RNA polymerase indicated that only the Ea29 form was able to transcribe the spoliD gene.This result is consistent with results of studies with the Spo-mutants, because only mutants that produced Ea29 were able to produce spollD mRNA in vivo. In the course of this work, two additional transcription units were discovered in the DNA region neighboring the spolID gene. One of these was expressed during vegetative growth; the other was expressed early during sporulation and corresponded to an in vitro transcript produced by the Eu29 form of RNA polymerase.Temporal control of gene expression during sporulation of Bacillus subtilis is thought to occur by sequential replacement of the sigma factor component of RNA polymerase (17,18). This mechanism can account for simultaneous activation and silencing of large groups of genes, even if they are scattered around the chromosome. In the last several years, this hypothesis has received strong experimental support. At least five forms of RNA polymerase (Ea55, Ea7, EJ32, Er29, Eu28) that differ only in their sigma factors are present in vegetative or sporulating cells or both. Each enzyme has specific promoter recognition sequences which permit it to transcribe only a certain group of genes (15). These genes are transcribed in vivo at characteristic times during growth or during sporulation or both.In vegetative cells, most of the RNA polymerase holoenzyme contains a sigma subunit designated {J55 (apparent molecular weight, 55,000). In an in vitro system, the purified form of this enzyme transcribes genes expressed in vivo during growth, such as the tms and veg genes (16, 20). Ear37 and E&2 are minor forms of RNA polymerase in vegetative cells. In vitro, these forms of RNA polymerase transcribe genes that are expressed at the end of the logarithmic growth phase or very early during sporulation (e.g., spoVG, ctc, and the subtilisin E gene) (15,27,31). Another minor form of vegetative cell RNA polymerase, Ea28, transcribes a small number of growth genes (13). The Ea29 form of RNA polymerase is found only in sporulating cells, and its appearance is developmentally regulated (30). It is most abundant about 3 h after sporulation begins; when it appears it seems to replace all known vegetative cell sigma factors (14, 30). Ea29 directs transcription of the L gene (14), as well as ctc (27) and, very weakly, the veg gene (14), ...

Role of the Anti-Sigma Factor SpoIIAB in Regulation of σ G during Bacillus subtilis Sporulation

“…We found that the GE156K protein accumulated starting 2 h after the onset of sporulation, reaching maximum levels around 3 h after sporulation had begun (Fig. 8B), which is in accordance with the temporal pattern of expression of a spoIID-lacZ fusion (36). In contrast, the wild-type form of G was detected only in trace amounts (Fig.…”

“…7). In contrast, expression of the spoIIIGE156K allele promptly resulted in sspE-lacZ expression, which occurred prior to normal expression of sspE in the prespore, in agreement with the timing of utilization of the spoIID and sspE promoters during sporulation (26,36) (Fig. 7).…”

“…Since G is autoregulatory and SpoIIAB is present in both the prespore and mother cell compartments, we wanted to determine whether SpoIIAB could have a role in the negative regulation of G in the mother cell, as previously suggested (3,8,19,21,35). To investigate this possibility, we fused the coding regions of the wild-type and spoIIIGE156K alleles to the mother cell-specific, E -dependent spoIID promoter (36). The fusions were transferred to the amyE locus of a strain bearing an in-frame deletion of the spoIIIG gene and an sspE-lacZ fusion (AH2452), yielding strains AH2460 (⌬spoIIIG sspE-lacZ P spoIID -spoIIIG) and AH2461 (⌬spoIIIG sspE-lacZ P spoIID -spoIIIGE156K) ( Table 1).…”

spoIIQ, a forespore‐expressed gene required for engulfment in Bacillus subtilis

“…Three loci have been identified in which mutations arrest sporulation at stage IIii: spoIID, spoIIM and spoIIP. These genes are all under the control of E and consequently their products are synthesized only in the mother cell (Rong et al, 1986;Driks and Losick, 1991;Frandsen and Stragier, 1995). The only available information on their role is provided by their sequence.…”

Cell-cell signaling pathway activating a developmental transcription factor in Bacillus subtilis.

“…Various deletions and disruptions were created in the immediate vicinity of the original fusion points. We checked the effect of these mutations on sporulation and (rE activity on solid media, by introducing them into a wild-type strain containing a fusion of lacZ to the (rE-controlled spolID promoter (Rong et al 1986). …”