Characterization of the partitioning system of Myxococcus plasmid pMF1.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 22174771.
- Also identified by DOI 10.1371/journal.pone.0028122 and PMC identifier PMC1595499.
- No licence information is recorded for this record.
- Because redistribution is not established, this page shows the abstract only. Follow the links below for the full text.
Abstract
pMF1 is the only autonomously replicating plasmid that has been recently identified in myxobacteria. This study characterized the partitioning (par) system of this plasmid. The fragment that significantly increased the retaining stability of plasmids in Myxococcus cells in the absence of selective antibiotics contained three open reading frames (ORFs) pMF1.21-pMF1.23 (parCAB). The pMF1.22 ORF (parA) is homologous to members of the parA ATPase family, with the highest similarity (56%) to the Sphingobium japonicum ParA-like protein, while the other two ORFs had no homologs in GenBank. DNase I footprinting and electrophoretic mobility shift assays showed that the pMF1.23 (parB) product is a DNA-binding protein of iteron DNA sequences, while the product of pMF1.21 (parC) has no binding activity but is able to enhance the DNA-binding activity of ParB to iterons. The ParB protein autogenously repressed the expression of the par genes, consistent with the type Ib par pattern, while the ParC protein has less repressive activity. The ParB-binding iteron sequences are distributed not only near the partitioning gene loci but also along pMF1. These results indicate that the pMF1 par system has novel structural and functional characteristics.