Genetic Studies of Leucine Biosynthesis in Bacillus subtilis

1991

Sporulation in Bacillus subtilis is a simple developmental system in which a single cell undergoes differentiation to two 'sister' cells, namely the prespore and the sporangium. Prespore-specific gene expression is largely dependent on the synthesis of a transcription factor, sigma G. Transcription of spolllG, the gene encoding sigma G, is under precise temporal and spatial control, requiring the products of at least eight genes that are expressed in the pre-divisional cell. Here we show that the product of one of these genes, another sigma factor, sigma F, is by itself sufficient to direct transcription of spolllG in non-sporulating cells. The results indicate that the cell-specificity of prespore gene expression is determined by a mechanism that exerts temporal and spatial control over the activity of sigma F.

Section: General Methodsmentioning

confidence: 99%

The role of σ^F in prespore‐specific transcription in Bacillus subtilis

Partridge

Foulger

1991

“…DNA preparation. Chromosomal DNA from B. subtilis was isolated either as described by Ward and Zahler (1973) (for transformation) or as described by En-ington (1984) (for cloning), Plasmid DNA from E. coliwas isolated by the method of Birnboim and Doly (1979). DNA fragments for subcloning were recovered from gels as described by .…”

Section: General Methodsmentioning

confidence: 99%

The spoIIIA operon of Bacillus subtilis defines a new temporal class of mother‐cell‐specific sporulation genes under the control of the σ^E form of RNA polymerase

Illing

1991

We have cloned and characterized a 5 kbp region of the Bacillus subtilis chromosome and show that it contains the promoter-proximal part of the spoIIIA locus. The locus consists of a polycistronic operon containing at least three genes. We show that the operon is regulated at the transcriptional level, from a promoter that is first activated about 80 minutes after the induction of sporulation, immediately after septation. Expression of spoIIIA in different spo mutant backgrounds correlates with the ability of each strain to synthesize the sporulation-specific sigma factor, sigma E. Moreover, synthesis of sigma E in vegetative cells by use of an inducible promoter causes expression of mother-cell-specific genes spoIID, spoIIIA, and spoIIID, but not the prespore-specific genes, spoIIIG and spoVA. We suggest that sigma E may be the primary determinant of mother-cell-specific gene expression and that the SpoIIID protein exerts an additional level of regulation on spoIIIA, apparently by acting as a transcriptional repressor. Since the onset of spoIIID expression occurs about 10 minutes after that of spoIIIA, spoIIIA expression is transient. Thus spoIIIA defines a third temporal class of gene controlled by the sigma E form of RNA polymerase.

“…Selection for chloramphanicol resistance was made on nutrient agar (Oxoid) containing chloramphenicol (5(i,g ml"'). Chromosomal DNA was Isolated from 6. subtiiis by the method of Ward and Zahler (1973). Strains of Escherichia coii were made competent and transformed either by the method described in the Amersham Ml3 Cioning and Sequencing Handbook or by the method of Hanahan (1985).…”

Section: General Methodsmentioning

confidence: 99%

Differential gene expression during sporulation in Bacillus subtilis: structure and regulation of the spoIIID gene

Stevens

1990

The gene spoIIID, which is essential for spore formation in Bacillus subtilis, was cloned and sequenced. It consists of one open reading frame which would encode a 93-amino-acid protein with a classic helix-turn-helix motif, characteristic of sequence-specific DNA-binding proteins. SpoIIID protein is a previously identified transcription factor, capable of altering the specificity of RNA polymerase containing sigma K in vitro (Kroos et al., 1989). The spoIIID83 mutation (by which the locus was originally identified), was sequenced and found to be a single base substitution in the ribosome binding site upstream of the spoIIID open reading frame. A transcriptional fusion to lacZ was constructed and used to examine the regulation of spoIIID. Expression of spoIIID occurred only during sporulation, beginning 1.5 to 2 hours after the initiation of sporulation. The dependence of spoIIID expression on other spo loci suggests that it is mother-cell-specific, and that it is transcribed by sigma E-containing RNA polymerase.