Tom Volpe, PhD

Assistant Professor of Cell and Molecular Biology
Feinberg School of Medicine

Research Interests:
Heterochromatin has been implicated in such diverse cellular processes as dosage compensation, imprinting, stem cell function, chromosome segregation, DNA repair and recombination. In addition, the role of heterochromatin in regulation of epigenetic changes in gene expression (heritable changes in gene expression that do not result from altered nucleotide sequence) has been recognized in a very broad range of eukaryotic species including animals, fungi and plants. The mechanisms by which cells establish and maintain heterochromatic domains, however, are not fully understood.

We employ a strong genetic system, the fission yeast Schizosaccharomyces pombe, as a model to study the regulation of heterochromatin in higher eukaryotes. Our previous studies in S. pombe have shed new light on establishment and maintenance of heterochromatic domains. We found that transcripts derived from heterochromatic centromeric repeat sequences are processed by the RNA interference (RNAi) machinery resulting in the sequence specific targeting of heterochromatin formation to these sequences. Similar phenomena have been observed in many eukaryotes including humans suggesting that RNA mediated heterochromatin formation is conserved throughout evolution.

We use a combination of genetic, molecular, and cellular approaches to better understand the mechanisms involved in RNAi dependent heterochromatin formation in fission yeast. The information gained from our studies will provide insight into the regulation of epigenetic phenomena in higher eukaryotes. This knowledge may also be extremely useful for the development of methods to combat human disease as well as strategies to study gene function.