关键词: 原核模式生物；RNA聚合酶；可替换型&sigma, 因子

Abstract: The sigma factor (σ factor) can recognize the functional sequences of the promoter in prokaryotic organism and is the cofactor of RNA polymerase. The σ factor exerts important function in gene transcriptional regulation. At present, many alternative sigma factors have been found in prokaryotic model organisms, in which 4 sigma factors found in Escherichia coli and 18 sigma factors in Bacillus subtilis. Based on the studies in the past, the classification, response mechanism, recognition elements and the structure character of sigma factors were presented in this paper. It would help for understanding the function of prokaryotic σ factors well and their contributions to the gene expression and regulation.

Key words: prokaryotic model organism, RNA polymerase, alternative sigma factors