Evidence is presented that the sporulationessential locus spolIG codes for both 29 subtilis strain with a mutation at the spolIG locus (spoIIG41).The appearance of P25 and P21 occurs in this mutant at a time when P31 and Ca29 would normally appear and suggests that they are homologous proteins. Transformation of the spoIlG41 strain with plasmid DNA carrying the structural gene for spolIG complements the Spo-phenotype and results in the synthesis of P31, a'29 p25, and P21 at the appropriate times during sporulation. In Escherichia coli, the cloned spolIG sequence encoded a protein that reacted with the anti-P31/Oa'29 monoclonal antibody and had the electrophoretic mobility of authentic P31.The spore-forming bacterium Bacillus subtilis synthesizes at least five forms of DNA-dependent RNA polymerase, which are distinguished by the promoter specificity determinant (o, factor) that each carries on a common core enzyme (1-5). One of the a-factors, cr29, is a protein (Mr, 29,000) that is detected only during endospore formation and was therefore predicted to be an important element of spore gene regulation (3, 6,

Sporulation of Bacillus subtilis involves sequential morphological and biochemical changes and is regulated by specific genes (spo genes) estimated to occupy more than 30 loci. A mutation in any one of these genes blocks the sporulation process at the corresponding developmental stage. Despite intensive genetic studies, the nature and function of the spo gene products remain unknown. Vegetative B. subtilis RNA polymerase core enzyme may interact with several sigma factors and discriminate among different classes of promoters. During sporulation, new polypeptides are associated with the core enzyme which may have a central role in modifying its promoter recognition specificity. As a first step to understanding their function in the switch from vegetative to sporulation mode, several early sporulation genes have been cloned and analysed. Here we report the cloning and nucleotide sequence of the spoIIG gene of B. subtilis. This gene encodes a polypeptide with a predicted relative molecular mass of 27,652 which contains a 65-amino acid region highly homologous to an internal part of the Escherichia coli sigma factor.

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The genes encoding the toxic determinants of Bacillus sphaericus have been expressed in a nontoxic and a toxic strain of Bacillus thuringiensis subsp. israelensis. In both cases, the B. sphaericus toxin proteins were produced at a high level during sporulation of B. thuringiensis and accumulated as crystalline structures. B. thuringiensis transformants expressing B. sphaericus and B. thuringiensis subsp. israelensis toxins did not show a significant enhancement of toxicity against Aedes aegypti, Anopheles stephensi, and Culex pipiens larvae.

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