Transcription regulation of the EcoRV restriction–modification system

When a plasmid containing restriction–modification (R–M) genes enters a naïve host, unmodified host DNA can be destroyed by restriction endonuclease. Therefore, expression of R–M genes must be regulated to ensure that enough methyltransferase is produced and that host DNA is methylated before the endonuclease synthesis begins. In several R–M systems, specialized Control (C) proteins coordinate expression of the R and the M genes. C proteins bind to DNA sequences called C-boxes and activate expression of their cognate R genes and inhibit the M gene expression, however the mechanisms remain undefined. Here, we studied the regulation of gene expression in the C protein-dependent EcoRV system. We map the divergent EcoRV M and R gene promoters and we define the site of C protein-binding that is sufficient for activation of the EcoRV R transcription

Steady-state levels of PRV•CR and PRV•M transcripts in the presence or in the absence of C

<p><b>Copyright information:</b></p><p>Taken from "Transcription regulation of the EcoRV restriction–modification system"</p><p>Nucleic Acids Research 2005;33(21):6942-6951.</p><p>Published online 6 Dec 2005</p><p>PMCID:PMC1310966.</p><p>© The Author 2005. Published by Oxford University Press. All rights reserved</p>EcoRV. RNA was purified from the HB101 cells harboring the indicated plasmids and primer extension reactions were performed to reveal 5′ end of divergent RNAs arising from the EcoRV regulatory region. The R primer allows the detection of rightward transcripts from pR or pM (PRV•CR or PRV•M transcripts, correspondingly). The L primer allows the detection of leftward transcripts from pR or pM (PRV•M or PRV•CR transcripts, correspondingly). The sequencing reactions' marker lanes were prepared using the pM or pR plasmids and primers used for primer extension