Yoshisue H, Nishimoto T, Sakai H, Komano T
Department of Agricultural Chemistry, Faculty of Agriculture, Kyoto University, Japan.
Gene. 1993 Dec 31;137(2):247-51. doi: 10.1016/0378-1119(93)90015-u.
The cryIVB gene of Bacillus thuringiensis subsp. israelensis (Bti) codes for a 135-kDa insecticidal crystal protein, which is specifically toxic to dipteran larvae. We have identified a transcription start point (tsp) of cryIVB by a primer extension experiment. The promoter sequence alignment, together with the chronology of appearance of the transcript, suggested that cryIVB is transcribed by RNA polymerase containing sigma 35 (E sigma 35). This was confirmed by investigation of cryIVB transcription in several Bacillus subtilis sporulation mutants. Unlike the lepidopteran-specific crystal protein-encoding genes [cryIA(a) and cryIB], transcription of which is regulated by both sigma 35 and sigma 28, cryIVB transcription was controlled only by the sigma 35-dependent promoter at the midsporulation stage.
苏云金芽孢杆菌以色列亚种（Bti）的cryIVB基因编码一种135 kDa的杀虫晶体蛋白，该蛋白对双翅目幼虫具有特异性毒性。我们通过引物延伸实验确定了cryIVB的转录起始点（tsp）。启动子序列比对以及转录本出现的时间顺序表明，cryIVB是由含有σ35（Eσ35）的RNA聚合酶转录的。通过对几种枯草芽孢杆菌芽孢形成突变体中cryIVB转录的研究证实了这一点。与鳞翅目特异性晶体蛋白编码基因[cryIA(a)和cryIB]不同，cryIA(a)和cryIB的转录受σ35和σ28调控，而cryIVB转录仅在芽孢形成中期受依赖于σ35的启动子控制。
