Talks From the 2013 MCDB Retreat

November 8, 2013

Guest post by Timothy Read

The 2013 MCDB retreat was held in Vail, Colorado the weekend of October 11th and as filled with 3 days of excellent science as presented during talks and at posters. I will summarize a couple of highlights from the scientific talks in this post.

The talks began Friday evening with an interesting take on the role of ploidy in evolution, presented by Dr. Robin Dowell. Robin highlighted results from her collaboration with the Pellman lab at the Dana Farber. By competing two alternately fluorescently labeled yet isogenic strains of S.cerevisiae and observing mutations in DNA sequence that accumulated over 240 generations, researchers were able to pinpoint mutations in pathways important for adaptation to raffinose containing media. Not surprisingly, mutations in hexose transporter genes were shown to be important for survival. However, more surprisingly, researchers showed that having an increased ploidy leads to more rapid adaptation. Results such as this are very important from an evolutionary standpoint and have broad applications for cancer research, as cancer cells are known to be wrought with aneuploidy.

Another cancer related theme was presented by Dr. Joaquin Espinosa. Dr. Espinosa showed compelling data on the transcription factor, p53, a tumor suppressor that is mutated in over 50% of cancers. A major take home point from this talk was that p53 acts solely as a transcriptional activator in the immediate response to activation. The discrepancy between this new finding and previous reports can be explained by the use of a new high throughput technology called GRO-seq, or global run on followed by sequencing. This technology is able to directly measure transcription, rather than the steady state transcript as measured by RNA-seq and expression microarray. Dr. Espinosa’s talk also examined a newly emerging class of RNA molecules termed eRNAs, or enhancer RNAs. After defining the complete list of transcriptional targets of p53, they found that eRNAs were expressed near the target genes and directly overlapping known p53 binding sites, suggesting that p53 binding may potentially cause the expression of these RNAs, or alternatively that these RNAs somehow influence binding of p53 to sequences in the DNA.

Another interesting talk was presented by Katie Heiser, a graduate student in the lab of Dr. Bob Garcea. Katie described ‘virus factories’ as domains within the nucleus of cells infected with mouse polyomavirus (MPyV) that are implicated in viral DNA replication. These factories form tube-like structures in infected nuclei imaged by EM. She described how infection of cells can lead to a drastic re-localization of host proteins, including a shift of DNA damage proteins toward these virus factories. Katie also showed that these factories are sites of viral DNA replication. Katie’s results could help elucidate more general mechanisms used by viruses to aid in infection and replication.

Overall, the 2013 MCDB retreat was a great success and helped stimulate discussion about projects going on in every lab. The MCDB retreat takes place every other year. On alternate years students put together a symposium in which several researchers from other Universities are invited to give talks at the University of Colorado. Planning for the 2014 MCDB graduate student symposium is underway and will be held in the fall. Keep an eye out for more information about the symposium!

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