DNA Looping in Prophage Lambda: New Insight from Single-Molecule Microscopy
The lambda (λ) bacteriophage epigenetic switch is a molecular mechanism that permits the quiescent (lysogenic) state of the bacteriophage to irreversibly switch to the virulent (lytic) state. After infection of its host, E. coli, λ, a temperate phage, most often grows lysogenically. The phage DNA integrates in the bacterial chromosome and is replicated along with it and transmitted to the bacterial progeny as a prophage. Lysogeny is very stable and yet, the switch to lysis is very efficient. Upon switching to lysis, the viral DNA is excised from the bacterial chromosome and the host machinery is used to produce viral progeny that is then released upon bursting of the host. The pathway to lysis is triggered in response to threats such as starvation, poisoning, or DNA damage.
KeywordsLoop Length Loop Formation Bacterial Chromosome Generalize Likelihood Ratio Test Transcription Assay
We would like to thank previous and current members of our groups whose research has facilitated these studies. We are also grateful to Haw Yang, who has provided reagents, analytical tools, and advice. The work described in this chapter was supported by the Italian Funding of Basic Research to LF and DDD, by the HFSP(RGP0050/2002-C) to L.F. and S.A., by the Intramural Research Program of the National Institutes of Health, National Cancer Institute and the Center for Cancer Research to S.A., by the Emory University Research Council and the NIH (RGM084070A) to LF.
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