LsrR-binding site recognition and regulatory characteristics in Escherichia coli AI-2 quorum sensing  

作　　者：Ting Xue Liping Zhao Haipeng Sun Xianxuan Zhou Baolin Sun 

机构地区：[1]Univ Sci & Technol China, Hefei Natl Lab Phys Sci Microscale, Hefei 230027, Peoples R China [2]Univ Sci & Technol China, Sch Life Sci, Hefei 230027, Peoples R China

出　　处：《Cell Research》2009年第11期1258-1268,共11页细胞研究（英文版）

基　　金：We thank our colleagues J Zang and X Liu for their technical assistance in protein purification. This work was supported by the One Hundred Talent Project of the Chinese Academy of Sciences and the National Natural Science Foundation of China （50738006）.

摘　　要：In quorum sensing （QS） process, bacteria regulate gene expression by utilizing small signaling molecules called autoinducers in response to a variety of environmental cues. Autoinducer 2 （AI-2）, a QS signaling molecule proposed to be involved in interspecies communication, is produced by many species of gram-negative and gram-positive bacteria. In Escherichia coil and Salmonella typhimurium, the extracellular AI-2 is imported into the cell by a transporter encoded by the lsr operon. Upstream of the lsr operon, there is a divergently transcribed gene encoding LsrR, which was reported previously to repress the transcription of the lsr operon and itself. Here, we have demonstrated for the first time that LsrR represses the transcription of the lsr operon and itself by directly binding to their promoters using gel shift and DNase I footprinting assays. The β-galactosidase reporter assays further suggest that two motifs in both the lsrR and lsrA promoter regions are crucial for the LsrR binding. Furthermore, in agreement with the conclusion that phosphorylated AI-2 can relieve the repression of LsrR in previous studies, our data show that phospho- AI-2 renders LsrR unable to bind to its own promoter in vitro.

关 键 词：quorum sensing LSRR AI-2 

分 类 号：Q78[生物学—分子生物学] Q939.1