Partition site of the P1 plasmid.

AUTOR(ES)

Martin, K A

RESUMO

We have defined a minimal partition site, parS, from the plasmid P1. It contains sufficient cis-acting information to direct accurate segregation of low-copy-number plasmids that contain it as long as the two essential P1 Par proteins are supplied in trans. The site is, at most, 34 base pairs and contains a perfect 13-base-pair inverted repeat. Site-directed mutations were made within the repeat sequence that abolished activity whether or not the symmetry of the palindrome was maintained. Partition appears to be a competitive process, as differentially marked plasmids carrying the same type of partition site are not independently segregated but are randomly distributed with respect to each other. We have studied competition between plasmids carrying various fragments encompassing the parS site. As expected, two plasmids carrying the minimal parS site compete with each other. However, a sequence that lies to the left of the minimal parS site acts as a major modulator of this competition, changing the specificity of the competitive effect completely. Thus, this adjacent sequence appears to be an important determinant of the specificity of the wild-type P1 partition system without being necessary for its efficient function.

Documentos Relacionados

• Fine-structure analysis of the P1 plasmid partition site.
• Maintenance of bacteriophage P1 plasmid.
• Effects of the P1 Plasmid Centromere on Expression of P1 Partition Genes
• Transcriptional Interference by a Complex Formed at the Centromere-Like Partition Site of Plasmid P1
• Participation of Escherichia coli integration host factor in the P1 plasmid partition system.