Sarah C. Elgin, PhD

Professor of Biology

Washington University in St. Louis (WU)

We are interested in the role that chromatin structure plays in gene regulation, both effects from packaging large domains and local effects of the nucleosome array. Working with Drosophila melanogaster, we have used a transposable P element containing a copy of the white gene, a visible marker for gene silencing, and a copy of hsp26, a well-characterized inducible gene, to examine the effect of insertion into different domains. Silencing (similar to Position Effect Variegation) is observed on insertion into pericentric heterochromatin, telomeres, and sites within the small fourth chromosome. Both changes in the local nucleosome array, and the spatial organization of the nucleus, appear critical. We are analyzing the process of heterochromatin formation, the mechanism of heterochromatin targeting (in particular the role of the RNAi machinery), and analyzing the role of critical heterochromatin-associated proteins, including HP1, HP2, and the histone methyltransferases.