Studholme D J, Buck M
Department of Biology, Imperial College of Science Technology and Medicine, Sir Alexander Fleming Building, London, UK.
FEMS Microbiol Lett. 2000 May 1;186(1):1-9. doi: 10.1111/j.1574-6968.2000.tb09074.x.
The bacterial transcription factor sigma(N) (sigma-N, sigma-54, RpoN) confers upon RNA polymerase (RNAP) properties distinct from those of the major house-keeping form of RNAP, which contains sigma(70) (sigma-70, RpoD). Transcription by RNAP containing sigma(N) is subject to enhancer-dependent regulation. Far from being an 'oddity' or 'exception to the rule', the occurrence of sigma(N) in the genome sequences of such diverse bacteria as Aquifex aeolicus, Bacillus subtilis, Chlamydia spp. and Borrelia burgdorferi argues for its biological importance. The availability of complete genome sequences of several (eu)bacteria offers an opportunity to extend our understanding of this special form of transcriptional regulation. By scanning their genome sequences, new functions have been predicted for enhancer-dependent transcription in A. aeolicus, Chlamydia trachomatis, Escherichia coli, Treponema pallidum and B. burgdorferi.
细菌转录因子σ(N)（σ-N、σ-54、RpoN）赋予RNA聚合酶（RNAP）一些特性，这些特性不同于含有σ(70)（σ-70、RpoD）的主要管家型RNAP的特性。含有σ(N)的RNAP进行的转录受到增强子依赖性调控。在诸如嗜热栖热菌、枯草芽孢杆菌、衣原体属和伯氏疏螺旋体等多种细菌的基因组序列中都存在σ(N)，这远非一种“奇特现象”或“规则的例外”，而是表明了其生物学重要性。几种（真）细菌完整基因组序列的可得性为我们扩展对这种特殊转录调控形式的理解提供了一个机会。通过扫描它们的基因组序列，已经预测出嗜热栖热菌、沙眼衣原体、大肠杆菌、梅毒螺旋体和伯氏疏螺旋体中增强子依赖性转录的新功能。
