RepA negatively autoregulates the transcription of the repABC operon of the Rhizobium etli symbiotic plasmid basic replicon.
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.
Ramírez-Romero
M A
MA
Programa de Evolución Molecular, Centro de Investigación sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Apartado Postal 565-A, Cuernavaca, Morelos, México.
Téllez-Sosa
J
J
Barrios
H
H
Pérez-Oseguera
A
A
Rosas
V
V
Cevallos
M A
MA
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D018983:DNA Footprinting; D004265:DNA Helicases; D004268:DNA-Binding Proteins; D015964:Gene Expression Regulation, Bacterial; D017930:Genes, Reporter; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009876:Operon / Q000235:genetics*; D011401:Promoter Regions, Genetic; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012231:Rhizobium / Q000235:genetics* / Q000502:physiology; D016415:Sequence Alignment; D015534:Trans-Activators; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D011506:Proteins; D011993:Recombinant Fusion Proteins; D015534:Trans-Activators; C045264:replication initiator protein; D004265:DNA Helicases