Presenter: Sabrina Abdulla
Faculty Mentor: Eric Selker, Vincent Bicocca
Presentation Type: Poster 42
Primary Research Area: Science
Major: Biology
Funding Source: OURS (Oregon Undergraduate Researchers in SPUR), NICDH, $4500
The regulation of epigenetic marks, including histone modifications and DNA methylation, is critical for normal development. Defects in the processes that regulate epigenetic marks can lead to the development of diseases, including cancer. To better understand these processes, we utilize the model organism Neurospora crassa, a filamentous fungus that possesses many epigllmerenetic marks that are common to higher order eukaryotes, including humans. Using this model, we have investigated the functional requirements of the DNA methyltransferase DIM-2, which is responsible for all DNA methylation in Neurospora. Using site-directed mutagenesis to systematically disrupt regions of DIM-2, and Southern blotting to assay DNA methylation, we discovered that the bromo-adjacent homology (BAH) domains of DIM-2 are required for normal DNA methylation activity. Based upon these observations, we hypothesized that the BAH domains are essential for making specific interactions with histone residues, and that these interactions are necessary for DIM-2 methyltransferase activity. To test this hypothesis, we utilized a DNA adenine methyltransferase (DAM) construct that allowed us to test the ability of the protein to localize to regions that are normally methylated based on the presence of adenine methylation. These experiments revealed that disruption of the BAH domains is sufficient to eliminate DIM-2 chromatin localization. Thus, the BAH domains prove to be essential for DNA methylation due to their role in DIM-2 localization.