13 research outputs found
Nucleoidâassociated Rok differentially affects chromosomal transformation on Bacillus subtilis
Rok, a Bacillus subtilis nucleoid-associated protein (NAP), negatively regulates competence development and silences xenogeneic genes. We show that rok inactivation increases rpoB482 natural intraspecies chromosomal transformation (CT) and plasmid transformation to a different extent. In ÎaddAB, ÎrecO, recF15, ÎrecU, ÎruvAB or rec+ cells intraspecies CT significantly increases, but the ÎrecD2 mutation reduces, and the ÎrecX, ÎradA or ÎdprA mutation further decreases CT in the Îrok context when compared to rok+ cells. These observations support the idea that rok inactivation, by altering the topology of the recipient DNA, differentially affects the integration of homologous DNA in rec-deficient strains, and in minor extent the competent subpopulation size. The impairment of other NAP (Hbsu or LrpC) also increased intra- and interspecies CT (nonself-DNA, ~8% nucleotide sequence divergence) in rec+ cells, but differentially reduced both types of CTs in certain rec-deficient strains. We describe that rok inactivation significantly stimulates intra and interspecies CT but differentially reduces them in transformation-deficient cells, perhaps by altering the nucleoid architecture. We extend the observation to other NAPs (Hbsu, LrpC)