Physics Colloquium - Friday, Feb. 22nd, 2008, 4:00 P.M.

E300 Math/Science Center; Refreshments at 3:30 P.M. in Room E200

John Marko
Department of Physics and Department of Biochemistry, Molecular Biology and Cell Biology
Northwestern University

Micromechanical study of DNA-protein interactions and chromosome structure

I will discuss the use of micromechanical assays - essentially measurements of elasticity - as methods to study how DNA is organized by being folded by proteins, ultimately into whole chromosomes. I will discuss studies at three scales of complexity. First, I will present results of single-DNA micromanipulation studies of proteins which compact the chromosome in the bacterium E. coli. I will then discuss how similar techniques can be applied to the study of the dynamics of assembly of nucleosomes into chromatin fiber onto a single DNA molecule. Finally I will discuss experiments which probe the internal organization of entire mitotic chromosomes isolated from dividing cells.