The Epigenetic Regulation of Transposable Elements: Reports from the front lines of the intra-genomes arms race.

Dr. Keith Slotkin
Ohio State University (Host: R. Mosher)
Tuesday, November 15, 2011 - 4:00pm
Marley 230

  Eukaryotic organisms defend the stability and integrity of their genome by suppressing the activity of transposable elements (TEs). In the plant, fungal and animal kingdoms, slightly different classes of small RNAs (sRNAs) target repressive chromatin modifications, such as DNA and histone tail methylation to TEs. The activity of these sRNAs renders the TE chromatin compacted and silenced. However, each cell and subsequent daughter generation does not determine "de novo" which sequences are TEs and should be silenced. Rather, this information is passed down from the progenitor cell or generation in a process termed epigenetic inheritance. The objective of our laboratory is to discover and understand how TE silencing is initiated and maintained across generations, as well as to characterize new forms of epigenetic gene regulation that have evolved from the evolutionarily arms race between TEs and the host genome. We have categorized where and when the epigenetic regulation of TEs are lost in the reference plant Arabidopsis: in mutants that lose symmetrical DNA methylation, long-term cultured cells, and nurse cells. In this last category, wild-type plants have a programmed activation of TEs in nurse cell types that are adjacent to much more important cells, such as gametes or meiocytes. Research projects in our laboratory focus on how TE silencing is initiated, the role of nurse cells in the propagation of epigenetic inheritance, and how TEs can regulate non-TE gene expression.