engleski

Chromosome segregation and cell morphology in recBC sbcBC ruvC mutants of Escherichia coli

The RuvC protein is important for DNA recombination and recombinational repair in E. coli. Together with RuvA and RuvB proteins, it is involved in the final, postsynaptic stage of recombination, in which Holliday intermediates are processed into mature recombinant products. In this work we have been focused on cytological effects provoked by a ruvC mutation in both wild type and recBC sbcBC backgrounds. By the usage of phase-contrast and fluorescence microscopy we have found that the ruvC mutation causes chromosome segregation and cell division defects in exponentially growing cells. These defects were extremely pronounced in recBC sbcBC ruvC mutants, in which about 50 % of population consisted of long filaments with unsegregated chromosomes. A small proportion of filaments displayed unusual shape irregularities including bulges and lateral appendages. Both chromosome segregation and cell division were significantly improved when additional recA mutation was introduced into the ruvC mutants. From these results we infer that chromosome segregation and cell division defects result from the abortive recombination initiated by the RecA protein. We hypothesize that unresolved chromosomes exert a negative effect on cell division process and that they affect cell wall structure.

nije evidentirano

nije evidentirano