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There is now a CONTENT FREEZE for Mercury while we switch to a new platform. It began on Friday, March 10 at 6pm and will end on Wednesday, March 15 at noon. No new content can be created during this time, but all material in the system as of the beginning of the freeze will be migrated to the new platform, including users and groups. Functionally the new site is identical to the old one. webteam@gatech.edu
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Prof. Laura Finzi, Emory University
Elucidation of the mechanism of the lambda bacteriophage epigenetic switch
Physical Chemistry/Biochemistry Divisions Seminar Series
The lambda bacteriophage epigenetic switch determines the growth lifestyle of the virus after infection of its host (/E. coli/). It is now clear that the switch consists of a ~2.3 kbp-long DNA loop mediated by the lambda repressor protein. Using tethered particle microscopy (TPM), magnetic tweezers and AFM, our laboratory has novel, direct evidence of loop formation and breakdown by the repressor, the first characterization of the thermodynamics and kinetics of the looping reaction and its dependence on DNA supercoiling and repressor non-specific binding. These /in vitro/ data provide insight into the different possible nucleoprotein complexes and into the lambda repressor-mediated looping mechanism which leads to predictions for that /in vivo/. The significance of this work consists not only of the new insight into a paradigmatic epigenetic switch that governs lysogeny vs. lysis, but also the detailed mechanics of regulatory DNA loops mediated by proteins bound to multipartite operators and capable of different levels of oligomerization.
For more information contact Prof. Christine Payne (404-385-3125).
