Integrated circuits: how transcriptional silencing and counter-silencing facilitate bacterial evolution.

Integrated circuits: how transcriptional silencing and counter-silencing facilitate bacterial evolution. Curr Opin Microbiol. 2014 Nov 5;23C:8-13 Authors: Will WR, Navarre WW, Fang FC Abstract Horizontal gene transfer is a major contributor to bacterial evolution and diversity. For a bacterial cell to utilize newly-acquired traits such as virulence and antibiotic resistance, new genes must be integrated into the existing regulatory circuitry to allow appropriate expression. Xenogeneic silencing of horizontally-acquired genes by H-NS or other nucleoid-associated proteins avoids adventitious expression and can be relieved by other DNA-binding counter-silencing proteins in an environmentally-responsive and physiologically-responsive manner. Biochemical and genetic analyses have recently demonstrated that counter-silencing can occur at a variety of promoter architectures, in contrast to classical transcriptional activation. Disruption of H-NS nucleoprotein filaments by DNA bending is a suggested mechanism by which silencing can be relieved. This review discusses recent advances in our understanding of the mechanisms and importance of xenogeneic silencing and counter-silencing in the successful integration of horizontally-acquired genes into regulatory networks. PMID: 25461567 [PubMed - as supplied by publisher]
Source: Current Opinion in Microbiology - Category: Microbiology Authors: Tags: Curr Opin Microbiol Source Type: research