Karambelkar, Shweta and Swapna, Ganduri and Nagaraja, Valakunja (2012) Silencing of toxic gene expression by Fis. In: NUCLEIC ACIDS RESEARCH, 40 (10). pp. 4358-4367.
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Bacteria and bacteriophages have evolved DNA modification as a strategy to protect their genomes. Mom protein of bacteriophage Mu modifies the phage DNA, rendering it refractile to numerous restriction enzymes and in turn enabling the phage to successfully invade a variety of hosts. A strong fortification, a combined activity of the phage and host factors, prevents untimely expression of mom and associated toxic effects. Here, we identify the bacterial chromatin architectural protein Fis as an additional player in this crowded regulatory cascade. Both in vivo and in vitro studies described here indicate that Fis acts as a transcriptional repressor of mom promoter. Further, our data shows that Fis mediates its repressive effect by denying access to RNA polymerase at mom promoter. We propose that a combined repressive effect of Fis and previously characterized negative regulatory factors could be responsible to keep the gene silenced most of the time. We thus present a new facet of Fis function in Mu biology. In addition to bringing about overall downregulation of Mu genome, it also ensures silencing of the advantageous but potentially lethal mom gene.
|Item Type:||Journal Article|
|Additional Information:||Copyright for this article belongs to the Authors of the Paper|
|Department/Centre:||Division of Biological Sciences > Microbiology & Cell Biology|
|Date Deposited:||27 Jun 2012 08:01|
|Last Modified:||27 Jun 2012 08:01|
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