The beta recombinase from the Streptococcal plasmid pSM 19035 represses its own transcription by holding the RNA polymerase at the promoter region.

AUTOR(ES)

Rojo, F

RESUMO

The beta protein encoded by the Streptococcus pyogenes plasmid pSM19035 is a site-specific recombinase involved in both resolution of plasmid multimers into monomers and DNA inversion. It has been proposed that the DNA region to which the beta recombinase binds to mediate recombination includes a promoter from which orf alpha and the beta gene are transcribed. We have determined the sites at which transcription of the orf alpha and the beta gene initiates in vitro and we have demonstrated that highly purified beta recombinase acts as a repressor of its own synthesis. The promoters are located within the beta recombinase binding site, which we have defined previously. The binding of the beta recombinase to its target site does not seem to exclude RNA polymerase from the promoter, despite the overlapping of their binding sites. Therefore, it is likely that the beta recombinase does not repress transcription by a mere steric hindrance on RNA polymerase binding.

Documentos Relacionados

• The beta recombinase of plasmid pSM19035 binds to two adjacent sites, making different contacts at each of them.
• Site-specific recombination by the beta protein from the streptococcal plasmid pSM19035: minimal recombination sequences and crossing over site.
• Revision of the nucleotide sequence of the Streptococcus pyogenes plasmid pSM19035 repS gene.
• Molecular analysis of the replication region of the conjugative Streptococcus agalactiae plasmid pIP501 in Bacillus subtilis. Comparison with plasmids pAM beta 1 and pSM19035.
• Plasmid copy-number control and better-than-random segregation genes of pSM19035 share a common regulator