Identification and characterization of two gcvA genes in Sinorhizobium meliloti

• 来源期刊: 科学通报(英文版)
• 年，卷（期）: 2009,（3）
• 页码范围: 405-411
• 页数: 7页
• 语种: 英文
• DOI: 10.1007/s11434-008-0516-x

摘要

GcvA is a member of the LysR family of transcriptional regulators that mediates the expression of the glycine cleavage (GCV) operon (gcvTHP) in response to glycine in Escherichia coil In our previous work, 90 putative regulator genes of the LysR family in Sinorhizobium meliloti were mutagenized to determine their phenotype. In the present study, we found that the S. mefiloti genome had two gcvA genes, gcvA1 and gcvA2. Both gcvA1 and gcvA2were required for full activation of the gcvTHPoperon in the presence of exogenous glycine. The gcvA1-mediated activation of gcvTHP operon was gly-cine-inducible, while gcvA2-mediated activation was not. We speculate that the regulatory mechanism for gcvTHP expression in S. meliloti differed from E. coiL Evolutionary analysis showed that GcvA were distributed in many genera of Proteobacteria and the distances between GcvA1 and GcvA2 in S. meliloti and GcvA in E. coil were large, which may explain the different regulatory mechanisms for gcvTHP expression. These findings could provide new clues to the role of the LysR gene family.