SPORULATION AND TIME-COURSE EXPRESSION OF SIGMA-FACTOR HOMOLOGOUS GENES IN CLOSTRIDIUM-ACETOBUTYLICUM

The gene for the vegetative sigma factor A of Clostridium acetobutylic um was constitutively transcribed during growth and formed an operon t ogether with dnaE. Sporulation-specific sigma factors E, G, and K were sequentially induced shortly before mature endospores could be detect ed. Maximal transcription in the course of spore formation was found t o be in the order sigE-sigG-sigK, thus matching the pattern described for Bacillus subtilis. From primer extension experiments promoter stru ctures could be deduced with high homology to the Bacillus consensus. Upstream of the spoIIGA-sigE operon a gene with significant similarity to ftsZ could be detected. (C) 1998 Federation of European Microbiolo gical Societies. Published by Elsevier Science B.V.