SIGMA(S)-DEPENDENT GROWTH-PHASE INDUCTION OF THE CSGBA PROMOTER IN ESCHERICHIA-COLI CAN BE ACHIEVED IN-VIVO BY SIGMA(70) IN THE ABSENCE OF THE NUCLEOID-ASSOCIATED PROTEIN H-NS
SIGMA(S)-DEPENDENT GROWTH-PHASE INDUCTION OF THE CSGBA PROMOTER IN ESCHERICHIA-COLI CAN BE ACHIEVED IN-VIVO BY SIGMA(70) IN THE ABSENCE OF THE NUCLEOID-ASSOCIATED PROTEIN H-NS
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DOI：
10.1111/j.1365-2958.1994.tb00493.x
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发表时间：
1994-09-01
影响因子：
3.6
通讯作者：
NORMARK, S
中科院分区：
文献类型：
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作者：
ARNQVIST, A;OLSEN, A;NORMARK, S
稳定期特异性sigma因子sigma（S）（RpoS/KatF）是大肠杆菌在达到稳定期时诱导纤维连接蛋白结合卷曲细胞器表达所必需的。我们发现，csgA基因编码的curlin亚基蛋白属于一个双顺反子操纵子，csgBA。确定了csgBA的转录起始位点，并鉴定了转录激活所需的富含AT的上游激活序列（UAS）。pcsgBA启动子对sigma（S）不是特异性的，因为相同的启动子序列可以在体内缺乏核苷相关蛋白H-NS和sigma（S）的菌株中被E sigma（70）使用。在这样的双突变体中，转录仍然是生长期诱导的，并且依赖于UAS。此外，我们证明了一个额外的操纵子hdeAB，它也依赖于sigma（S）的转录，可以在体内转录的E sigma（70）在没有H-NS通过利用phdeAB启动子。已知在sigma（S）控制下表达的另外两个基因bolA和katE在不存在H-NS的情况下保持转录沉默。建议将E.大肠杆菌启动子在体内可被E sigma（S）和E sigma（70）识别，但与这些序列相互作用的H-NS阻止与E sigma（70）形成成功的转录起始复合物。
The stationary-phase-specific sigma factor sigma(S) (RpoS/KatF) is required for Escherichia coli to induce expression of fibronectin-binding curli organelles upon reaching stationary phase. We show that the csgA gene which encodes the curlin subunit protein belongs to a dicistronic operon, csgBA. The transcriptional start site of csgBA was determined and an AT-rich upstream activating sequence (UAS) required for transcriptional activation was identified. The pcsgBA promoter is not specific for sigma(S) since the same promoter sequence can be used by E sigma(70) in vivo in a strain lacking nucleoid-associated protein H-NS and sigma(S). Transcription remained growth-phase induced and dependent upon the UAS in such a double mutant. Furthermore, we demonstrate that an additional operon, hdeAB, which is also dependent upon sigma(S) for transcription, can be transcribed by E sigma(70) in vivo in the absence of H-NS by utilizing the phdeAB promoter. Two other genes known to be under the control of sigma(S) for expression, bolA and katE, remained transcriptionally silent in the absence of H-NS. It is suggested that a subset of E. coli promoters can be recognized by both E sigma(S) and E sigma(70) in vivo but H-NS interacting with these sequences prevents formation of succesful transcription-initiation complexes with E sigma(70).