Stevens C M, Errington J
Department of Biochemistry, University of Oxford, UK.
Mol Microbiol. 1990 Apr;4(4):543-51. doi: 10.1111/j.1365-2958.1990.tb00622.x.
The gene spoIIID, which is essential for spore formation in Bacillus subtilis, was cloned and sequenced. It consists of one open reading frame which would encode a 93-amino-acid protein with a classic helix-turn-helix motif, characteristic of sequence-specific DNA-binding proteins. SpoIIID protein is a previously identified transcription factor, capable of altering the specificity of RNA polymerase containing sigma K in vitro (Kroos et al., 1989). The spoIIID83 mutation (by which the locus was originally identified), was sequenced and found to be a single base substitution in the ribosome binding site upstream of the spoIIID open reading frame. A transcriptional fusion to lacZ was constructed and used to examine the regulation of spoIIID. Expression of spoIIID occurred only during sporulation, beginning 1.5 to 2 hours after the initiation of sporulation. The dependence of spoIIID expression on other spo loci suggests that it is mother-cell-specific, and that it is transcribed by sigma E-containing RNA polymerase.
对枯草芽孢杆菌孢子形成所必需的基因spoIIID进行了克隆和测序。它由一个开放阅读框组成，该开放阅读框编码一个含有经典螺旋-转角-螺旋基序的93个氨基酸的蛋白质，这是序列特异性DNA结合蛋白的特征。SpoIIID蛋白是一种先前鉴定的转录因子，能够在体外改变含有σK的RNA聚合酶的特异性（Kroos等人，1989年）。对spoIIID83突变（最初通过该突变鉴定该基因座）进行了测序，发现它是spoIIID开放阅读框上游核糖体结合位点的单个碱基替换。构建了与lacZ的转录融合体，并用于研究spoIIID的调控。spoIIID的表达仅在孢子形成期间发生，在孢子形成开始后1.5至2小时开始。spoIIID表达对其他spo基因座的依赖性表明它是母细胞特异性的，并且由含有σE的RNA聚合酶转录。
