Department of Biology


All seminars are in DSB 130 at 11:20 AM unless otherwise noted

Sept. 3 – Chris Herlihy, MTSU (tenure and promotion seminar)

Sept. 17 – Mary Farone, MTSU (tenure and promotion seminar)

Sept. 19 – Matt Klukowski, MTSU (tenure and promotion seminar)

Sept. 24 – Rob Brucker, Vanderbilt University

Oct. 8 – Kirk Zigler, University of the South

Oct. 22 - Wail El-rafai, Vanderbilt University

Oct. 24 – Elliot Altman, MTSU

Oct. 29 – Rob McFeeters, University of Alabama, Huntsville

Nov. 5 – Joel Harp, Vanderbilt University

Nov. 12 – Ken Spitze, Indiana University

Nov. 19 – Joey Shaw, Department of Biological and Environmental Sciences, University of Tennessee, Chattanooga

Nov. 21 - Jeff Leblond, Department of Biology, MTSU

Nov. 26 – Manoj Khadka, MTSU

Dec. 3 - John Niedzwiecki, Belmont University

Jan. 21 – Brian Robertson, MTSU (3rd year review seminar)

Jan. 28 – Iris Gao, MTSU (3rd year review seminar)

Feb. 4 – Shawn Crosnick, Tennessee Tech

Feb. 11 – Josh Dodson, Department of Biology, MTSU

Feb. 18 – Ivonne Garzon, MTSU

Feb. 25 –  Drew Sieg, MTSU

Mar. 20 -  Tiffany Guess, MTSU

Mar. 25 – Charles Chusuei, MTSU

Mar. 27 -  Bam Paneru, MTSU

Apr. 8  -   Mulugeta Wayu, MTSU

Apr. 10 -  Penny Carroll, MTSU

Apr. 15 -  Megan Stallard and Amy Shaffer, MTSU

Apr. 17 -  Nadin Almonsid, MTSU

Apr. 22 -  Julie Hosain, MTSU

Apr. 24 - CANCELLED - Jennifer R. Mandel, Univ. of Memphis

Apr. 29 - Bill Tansey, Vanderbilt University Medical Center
Ubiquitin and Proteasomes in Transcription
It has recently become clear that the ubiquitin (Ub)–proteasome system (UPS) influences a multitude of key steps in gene expression, ranging from regulation of transcriptional activators and co-activators through to control of mRNA export from the nucleus. One particularly interesting example of how the UPS impacts transcription centers on the proteasome. Studies have implicated both the proteolytic and non-proteolytic activities of the proteasome as being important for a number of transcriptionally-relevant processes, but controversy exists as to the form of the proteasome that participates in transcription and the extent to which its various activities regulate the transcriptome. We have recently developed a number of tools that allow us to monitor the association of native proteasome subunits with chromatin and to examine the effects of comprehensive proteasome inhibition on patterns of gene activity in the yeast Saccharomyces cerevisiae. Using these reagents, we have probed the physical and functional interaction of proteasomes with active chromatin using both gene-specific and genome-wide approaches. Our data reveal that 19S lid, 19S base, and 20S core proteasome subunits associate with chromatin in a virtually indistinguishable manner, supporting the idea that the form of the proteasome that is recruited to chromatin is the canonical 26S complex. We find that proteasomes interact with a large and diverse set of genes in yeast and are typically enriched within the transcribed portions of these genes. Association of proteasome subunits with active chromatin is transcription-dependent, but surprisingly only a subset of genes bound by the proteasome depend on its proteolytic activity for their expression. The widespread and overlapping nature of 19S and 20S subunit binding to chromatin, together with the differential requirement for 20S function at select genes, suggests to us that different activities of the proteasome are being employed at different sites of transcription. We propose that the 26S proteasome acts as a kind of 'Swiss Army knife' in transcription—an integrated set of biological functions that are recruited en masse to transcriptionally active genes, but sampled individually depending on the particular characteristics of the gene that is being transcribed.