title: Characteristics of the LrhA subfamily of transcriptional regulators from Sinorhizobium meliloti.
abstract: 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 alpha, beta, and gamma subdivisions of proteobacteria, and a few in actinobacteria. These findings could provide new clues to the roles of the LysR gene family.
authors.affiliation: Laboratory of Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China.
authors.forename: Mingsheng
authors.initials: M
authors.lastname: Qi
authors.forename: Li
authors.initials: L
authors.lastname: Luo
authors.forename: Haiping
authors.initials: H
authors.lastname: Cheng
authors.forename: Jiabi
authors.initials: J
authors.lastname: Zhu
authors.forename: Guanqiao
authors.initials: G
authors.lastname: Yu
mesh_terms: D054742:Acyl-Butyrolactones / Q000378:metabolism; D016960:Agrobacterium tumefaciens / Q000235:genetics; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009068:Movement; D005810:Multigene Family; D009154:Mutation; D010957:Plasmids / Q000235:genetics; D020560:Proteobacteria / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D016962:Sinorhizobium meliloti / Q000235:genetics* / Q000378:metabolism* / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism*
chemical_list: D054742:Acyl-Butyrolactones; D001426:Bacterial Proteins; C095974:LrhA protein, bacteria; D014157:Transcription Factors; C073470:LysR protein, Bacteria