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RepA negatively autoregulates the transcription of the repABC operon of the Rhizobium etli symbiotic plasmid basic replicon
Author(s) -
RamírezRomero Miguel A.,
TéllezSosa Juan,
Barrios Humberto,
PérezOseguera Angeles,
Rosas Vania,
Cevallos Miguel A.
Publication year - 2001
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.2001.02621.x
Subject(s) - operon , replicon , biology , plasmid , genetics , transcription (linguistics) , gene , l arabinose operon , promoter , microbiology and biotechnology , lac operon , escherichia coli , gene expression , linguistics , philosophy
The basic replicon of Rhizobium etli CE3, like other members of the repABC plasmid family, is constituted by the repABC operon. RepC is essential for replication, and RepA and RepB play a role in plasmid segregation. It has been shown that deletion derivatives lacking the repAB genes have an increased copy number, indicating that these genes participate in the control of plasmid copy number. RepA is also a trans ‐incompatibility factor. To understand the regulation of the repABC operon, in this paper: (i) the transcription start site of the repABC operon was determined; (ii) the promoter region was identified by site‐directed mutagenesis of the putative −35 and −10 hexameric elements; and (iii) RepA was recognized as a negative regulator of the transcription of the repABC operon.