van Sinderen D, Luttinger A, Kong L, Dubnau D, Venema G, Hamoen L
Department of Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Haren, The Netherlands.
Mol Microbiol. 1995 Feb;15(3):455-62. doi: 10.1111/j.1365-2958.1995.tb02259.x.
comK is a positive autoregulatory gene occupying a central position in the competence-signal-transduction network. All regulatory routes identified in this network converge at the level of comK expression. The ComK protein is required for the transcriptional induction of comK and the late competence genes, which specify morphogenetic and structural proteins necessary for construction of the DNA-binding and uptake apparatus. In this report we demonstrate that ComK specifically binds to DNA fragments containing promoter and upstream sequences of the genes it affects (comC, comE, comF, comG and comK). Using portions of the region upstream of comC we show that the ComK-binding sequences are essential for the expression of competence. Moreover, we demonstrate that the presence of ComK stimulates the expression of comF-lacZ and comG-lacZ translational fusions in vivo in Escherichia coli. These results indicate that the gene product of comK is identical to the previously inferred competence transcription factor (CTF).
comK是一个正向自调控基因，在感受态信号转导网络中占据核心位置。该网络中已确定的所有调控途径都在comK表达水平上汇聚。ComK蛋白是comK和晚期感受态基因转录诱导所必需的，这些基因指定了构建DNA结合和摄取装置所需的形态发生和结构蛋白。在本报告中，我们证明ComK特异性结合包含其影响的基因（comC、comE、comF、comG和comK）启动子和上游序列的DNA片段。使用comC上游区域的部分序列，我们表明ComK结合序列对于感受态的表达至关重要。此外，我们证明ComK的存在会在体内刺激大肠杆菌中comF-lacZ和comG-lacZ翻译融合体的表达。这些结果表明，comK的基因产物与先前推断的感受态转录因子（CTF）相同。
