Transcriptional regulation of Bacillus thuringiensis subsp. israelensis mosquito larvicidal crystal protein gene cryIVA.

The cryIVA gene encodes a component of the delta-endotoxin of Bacillus thuringiensis subsp. israelensis. By S1 nuclease mapping and primer extension analysis, we have identified the transcriptional initiation site of cryIVA. The transcriptional activity from the promoter was detected only for the sporulating cells more than 3 h after onset of the stationary phase. Upstream from the cryIVA transcriptional initiation site was found a nucleotide sequence partially homologous to the promoter consensus sequence for the E sigma E holoenzyme of Bacillus subtilis. Thus, it was strongly suggested that the identified cryIVA promoter, like some other crystal protein gene promoters, was under the control of sigma 35, the B. thuringiensis homolog of sigma E.