Characteristics of the LrhA subfamily of transcriptional regulators from Sinorhizobium meliloti  

作　　者：Mingsheng Qi Li Luo Haiping Cheng Jiabi Zhu Guanqiao Yu 

机构地区：[1]Laboratory of Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Shanghai Institute for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China [2]Graduate School of the Chinese Academy of Science s, Beijing 100049, China [3]Biological Sciences Department, Lehman College, City University of New York, New York 10468, USA

出　　处：《Acta Biochimica et Biophysica Sinica》2008年第2期166-173,共8页生物化学与生物物理学报（英文版）

摘　　要：In our previous work, we identified 94 putative genes encoding LysR-type transcriptional regulators from Sinorhizobium meliloti. All of these putative lysR genes were mutagenized using plasmid insertions to determine their phenotypes. Six LysR-type regulators, encoded by mutants SMa1979, SMb20715, SMc00820, SMc04163, SMc03975, and SMc04315, showed similar amino acid sequences （30 %） and shared the conserved DNA-binding domain with LrhA, HexA, or DgdR. Phenotype analysis of these gene mutants indicated that the regulators control the swimming behaviors of the bacteria, production of quorum-sensing signals, and secretion of extracellular proteins. These characteristics are very similar to those of LrhA, HexA, and DgdR. Thus, we refer to this group as the LrhA subfamily. Sequence analysis showed that a great number of homologous genes of the LrhA subfamily were distributed in the α, β, and γsubdivisions of proteobacteria, and a few in actinobacteria. These findings could provide new clues to the roles of the LysR gene family.In our previous work, we identified 94 putative genes encoding LysR-type transcriptional regulators from Sinorhizobium meliloti. All of these putative lysR genes were mutagenized using plasmid insertions to determine their phenotypes. Six LysR-type regulators, encoded by mutants SMa1979, SMb20715, SMc00820, SMc04163, SMc03975, and SMc04315, showed similar amino acid sequences （30 %） and shared the conserved DNA-binding domain with LrhA, HexA, or DgdR. Phenotype analysis of these gene mutants indicated that the regulators control the swimming behaviors of the bacteria, production of quorum-sensing signals, and secretion of extracellular proteins. These characteristics are very similar to those of LrhA, HexA, and DgdR. Thus, we refer to this group as the LrhA subfamily. Sequence analysis showed that a great number of homologous genes of the LrhA subfamily were distributed in the α, β, and γsubdivisions of proteobacteria, and a few in actinobacteria. These findings could provide new clues to the roles of the LysR gene family.

关 键 词：LrhA subfamily LysR-type transcriptionalregulator Sinorhizobium meliloti 

分 类 号：Q78[生物学—分子生物学]