PLANT SCIENCES INSTITUTE SEMINAR SERIES
Sarah C. R. Elgin, Ph.D.
Viktor Hamburger Professor of Arts and Sciences; Professor, Department of Biology
Washington University, St. Louis
Living with your Genome: A Fly’s Eye View of Dealing with Repeats
Wednesday, April 6
4:10 to 5 p.m.
1414 Molecular Biology Building
Eukaryotic genomes are surprisingly large, apparently a consequence of invasion by transposable elements (TEs). Such elements are generally targeted for silencing, often through heterochromatin formation. Drosophila has proven to be an excellent system for studying the nature of heterochromatin and the possible mechanisms for targeting heterochromatin formation. Our results indicate that while both TE remnants and tandem repeat arrays (a lacO array and GAA triplet repeat) are targeted for silencing, proximity to a heterochromatic mass is also important, suggesting a spreading effect. The RNAi system appears to be involved in at least some TE cases. Formation of heterochromatin occurs just prior to blastoderm in the early embryo; assembly deficits at that time lead to adult phenotypes. While HP1a is consistently involved, there appear to be some variations in the way histone modifications are used in heterochromatin structure. Whether or not we can establish common principles of targeting and assembly for all types of repeats remains an intriguing question.
Please join us for refreshments at 3:45 in the Molecular Biology Building Atrium.