Yoshisue H, Ihara K, Nishimoto T, Sakai H, Komano T
Department of Agricultural Chemistry, Faculty of Agriculture, Kyoto University, Japan.
FEMS Microbiol Lett. 1995 Mar 15;127(1-2):65-72. doi: 10.1111/j.1574-6968.1995.tb07451.x.
To investigate the mechanism of transcriptional regulation of cryIVA and cryIVB, encoding 130-kDa dipteran-active crystal proteins, in Bacillus thuringiensis subsp. israelensis, we introduced each gene into several sporulation mutants of Bacillus subtilis. A spoIIG mutation, the wild-type gene of which encodes sigma E precursor, completely blocked the cryIVB transcription. In contrast, low but detectable transcription of cryIVA was observed in the spoIIG mutant. In the wild-type B. subtilis, no transcription of cryIVB was detected before T2 (2 h after the onset of stationary phase), while the cryIVA transcription started at the late exponential phase at low levels. Furthermore, in a wild-type strain of B. thuringiensis subsp. israelensis, transcription of cryIVA began earlier than that of genes encoding other crystal components, cryIVB and cytA. A consensus sequence recognized by an RNA polymerase containing sigma H of B. subtilis was found upstream of the transcription start point of cryIVA, which overlapped with that recognized by sigma E.
为了研究苏云金芽孢杆菌以色列亚种中编码130-kDa双翅目活性晶体蛋白的cryIVA和cryIVB的转录调控机制，我们将每个基因导入枯草芽孢杆菌的几个芽孢形成突变体中。spoIIG突变（其野生型基因编码σE前体）完全阻断了cryIVB的转录。相反，在spoIIG突变体中观察到cryIVA有低水平但可检测到的转录。在野生型枯草芽孢杆菌中，在T2（稳定期开始后2小时）之前未检测到cryIVB的转录，而cryIVA的转录在指数后期开始，水平较低。此外，在苏云金芽孢杆菌以色列亚种的野生型菌株中，cryIVA的转录比编码其他晶体成分的基因cryIVB和cytA的转录开始得更早。在cryIVA转录起始点上游发现了一个由含有枯草芽孢杆菌σH的RNA聚合酶识别的共有序列，该序列与σE识别的序列重叠。
