Class of 2005
zhensel@jhu.edu | Double major - B.S. Physics, B.A. Cinema Studies, University of Illinois at Urbana-Champaign
Research
Genetic regulatory networks are capable of maintaining concentrations of proteins and regulatory molecules at well defined concentrations and spatial distributions in every cell and organism. This is essential for highly specific developmental processes and rapid response to environmental change. When lambda phage infects a bacterium and incorporates its genetic information into the bacterial chromosome, it will maintain this quiescent for millions of cycles of cell division without spontaneously leaving the chromosome. However, excision of phage DNA, phage replication, and cell lysis occur within an hour. A single protein, lambda repressor CI, regulates this stable state, simultaneously promoting its own expression, repressing expression of other phage genes, and repressing its own expression at high concentrations. We have developed a single-molecule reporter of CI translation in E. coli in which each CI molecule is cotranslationally detected by a membrane-targeted fluorescent reporter. The reporter and regulator are proteolytically cleaved in vivo, allowing CI to perform its
regulatory function without perturbation and providing one-to-one visualization of CI synthesis.
Publications
Barry, E., Z. Hensel, and Z. Dogic. (2006) Entropy-driven formation of a chiral liquuid-crystalline phase of helical filaments. Phys. Rev. Lett. 96:018305. PMID: 16486530
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