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The regulation of transcription of the gerA spore germination operon of Bacillus subtilis
Author(s) -
Feavers I. M.,
Foulkes J.,
Setlow B.,
Sun D.,
Nicholson W.,
Setlow P.,
Moir A.
Publication year - 1990
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1990.tb00594.x
Subject(s) - biology , bacillus subtilis , operon , transcription (linguistics) , germination , spore , spore germination , microbiology and biotechnology , botany , genetics , bacteria , gene , escherichia coli , linguistics , philosophy
Summary The gerA operon of Bacillus subtilis 168 comprises three genes concerned with the triggering of spore germination by l ‐alanine and its analogues. The expression of this operon has been characterized using chromosomal lacZ fusions to the gerA promoter. The gerA promoter is switched on 2.5–3 hours after the initiation of sporulation, in parallel with glucose dehydrogenase. A high proportion of the gerA ‐driven β‐galactosidase detected in sporulating cells is found in the mature spore; the gerA promoter is therefore active in the forespore compartment of the sporulating cell. The gerA promoter is not expressed in spo 0, spo II or spoIIIA, B, E and G mutant backgrounds, but is expressed in spoIIIC and D and in spoIV and V mutants. The in vivo transcriptional startpoint of the operon has been mapped by primer extension experiments; sequences upstream from this startpoint show significant homology with recognition sequences for RNA polymerase containing σ G (Eσ G ). The gerA operon was transcribed in vitro by Eσ G with a startpoint identical to that used in vivo , and expression of the gerA operon was rapidly induced in vegetative cells by induction of σ G synthesis. These data indicate that the gerA operon is an additional member of the σ G regulon, which includes a number of genes expressed in parallel only in the forespore compartment of sporulating B. subtilis cells.