Identification of a promoter for the crystal protein-encoding gene cry1Ia from Bacillus thuringiensis subsp. kurstaki.

Expression of cry1Ia, one of the insecticidal protein genes of Bacillus thuringiensis subsp. kurstaki, was studied at the transcriptional level. By primer extension analysis, we have identified for the first time, the transcription start point of cry1Ia. Upstream from the cry1Ia transcription start point, was found a nucleotide sequence partially homologous to the consensus sequence for the E sigma(E) holoenzyme of Bacillus subtilis. Thus, it was strongly suggested that the identified cry1Ia promoter was under the control of sigma(35), the B. thuringiensis homolog of sigma(E). The transcriptional activity from the promoter was detected only for the sporulating cells at T2 and T5 stages.