Transcriptional interference and repression modulate the conjugative ability of the symbiotic plasmid of Rhizobium etli
Por:
Sepúlveda E., Pérez-Mendoza D., Ramírez-Romero M.A., Soto M.J., López-Lara I.M., Geiger O., Sanjuán J., Brom S., Romero D.
Publicada:
1 jun 2008
Resumen:
Bacteria of the order Rhizobiales are able to establish nitrogen-fixing symbioses with legumes. Commonly, genes for symbiosis are harbored on large symbiotic plasmids. Although the transfer of symbiotic plasmids is commonly detected in nature, there are few experimentally characterized examples. In Rhizobium etli, the product of rctA inhibits the conjugation of the symbiotic plasmid by reducing the transcription of the virB operon. rctA is transcribed divergently from this operon, and its product is predicted to have a DNA binding domain. In the present study, using DNase I footprinting and binding assays, we demonstrated the specific binding of RctA to the virB operon promoter. A 9-bp motif in the spacer region of this promoter (the rctA binding motif box) and the presence of a functional -10 region were critical elements for RctA binding. Transcriptional fusion analyses revealed that the elimination of either element provoked a relief of RctA-mediated repression. These data support a
Filiaciones:
Sepúlveda E.:
Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, Cuernavaca, Morelos, Mexico
Pérez-Mendoza D.:
Estación Experimental del Zaidín, CSIC, Granada, Spain
Ramírez-Romero M.A.:
Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, Cuernavaca, Morelos, Mexico
Soto M.J.:
Estación Experimental del Zaidín, CSIC, Granada, Spain
López-Lara I.M.:
Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, Cuernavaca, Morelos, Mexico
Geiger O.:
Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, Cuernavaca, Morelos, Mexico
Sanjuán J.:
Estación Experimental del Zaidín, CSIC, Granada, Spain
Brom S.:
Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, Cuernavaca, Morelos, Mexico
Romero D.:
Univ Nacl Autonoma Mexico, Ctr Ciencias Genom, Program Ingn Genom, Cuernavaca 62210, Morelos, Mexico
Bronze
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