Laurie Stargell
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| Stargell, Laurie - Professor |
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| Laurie.Stargell@ColoState.edu |
| Office Number: 379 MRB |
| Phone Number: (970) 491-5068 |
| Fax Number: (970) 491-0494 |
| Research Title: |
| Mechanisms of Transcription Initiation in Yeast: The Role TBP and TFIIA in Regulated Expression |
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| Initiation of transcription by RNA polymerase (pol) II is the major site for regulation of eukaryotic gene expression during cell cycle progression, development and physiological induction. The formation of a functional initiation complex is highly dependent on the TATA element, a core promoter element that directs the precise positioning of TFIID, a multi-subunit protein consisting of the TATA binding protein (TBP) and at least a dozen TBP associated factors (TAFs). TBP plays a critical role in pol II transcription initiation because it specifically recognizes and binds to the TATAAA sequence of the core promoter allowing for the nucleation of other general transcription factors and RNA polymerase II. Our work combines the powerful genetic, molecular, and biochemical methods available in the yeast Saccharomyces cerevisiae, to investigate a variety of topics with the main objective of understanding the mechanisms that regulate transcription initiation by pol II in vivo. Of particular interest to us are studies of structural/functional aspects of yeast TBP and TFIID, and functional interactions between TBP and DNA. We are using biochemical and biophysical techniques to probe the mechanistic defects of three distinct classes of TBP mutants: 1) defective for TFIIA interaction; 2) defective for TFIID formation; and 3) defective for post-recruitment functions of TBP. Continued genetic suppressor analyses of these and other TBP mutants will lead to the identification of factors that functionally interact with TBP. With regards to TBP-DNA interactions, it is clear that natural TATA elements often do not conform precisely to the consensus TATAAA sequence and these variations can alter promoter strength, presumably via changes in the quality of the TBP-TATA element interaction. We are using biochemical, biophysical and genetic studies to determine what factor(s) play a role in initiation at strong versus weak elements. Our findings to date suggest that TBP, which binds DNA rather promiscuously, is unable to distinguish between different strength promoter elements in vitro. In contrast, the TFIIA-TBP complex is very sensitive to the apparent quality of the TATA element. We are currently determining the molecular mechanisms by which TFIIA participates with TBP in determining promoter strength and we are also interested in identifying the protein-protein interactions necessary for these functions. We have observed that TFIIA interacts with other factors in the pol II complex in addition to TBP. A combination of techniques, including classical and molecular yeast genetics, and protein biochemistry, are being used to probe the structural and functional properties of TFIIA and TFIIA-interacting proteins. Our multi-faceted approach, which combines genetics, biochemistry and biophysical techniques, assures the biological relevance of the characterized interactions. Since the proteins identified to date are highly conserved in both sequence and function from yeast to humans, a complete understanding of the roles of these proteins in the regulation of gene expression will undoubtedly provide important new information that is directly relevant to basic transcription mechanisms. This is particularly important since many human diseases (including cancer) are caused by abnormal gene regulation. |
Selected Publications: |
| Ranallo, R.T., K. Struhl, and L.A. Stargell
(1999). A TBP mutant defective for TFIID
formation in vivo. Molecular and Cellular
Biology 19: 3951-3957. Campell, K.M., R.T. Ranallo, L.A.Stargell and K.J. Lumb (2000). Reevaluation of transcriptional regulation by TATA binding protein oligomerization: Predominance of Monomers. Biochemistry 39:2633-2638 Stargell, L.A., Z. Moqtaderi, D.R. Dorris, R. Ogg and K. Struhl (2000). Coactivator and core promoter functions of the TFIIA-TBP interaction. Journal of Biological Chemistry 275:12374-12380. Kraemer, S.M., R.T. Ranallo, R.C. Ogg, and L.A. Stargell (2001). TFIIA interacts with TFIID via association with TBP and TAF40. Molecular and Cellular Biology 5:1737-46. Stargell, L.A., R.C. Ogg, J.N. Adkins, M M. Robinson and K.J. Lumb (2001). Transcriptional Activity of the TFIIA Four-Helix Bundle in vivo. Proteins 43:227-32. Stewart J.J. and L.A. Stargell (2001). The stability of the TFIIA-TBP-DNA complex is dependent on the sequence of the TATAAA element. Journal of Biological Chemistry, in press. Stewart, J.J. and L.A. Stargell. (2001). The stability of the TFIIA-TBP-DNA complex is dependent on the sequence of the TATAAA element. J. Biol. Chem. 276, 30078-84. Kraemer,S.M., R.T. Ranallo, R.C. Ogg and L.A. Stargell (2001) TFIIAinteracts with TFIID via association with TBP and TAF40. Molec. AndCell. Biology 5, 1737-46. Fischbeck,J.A., S.M. Kraemer, and L.A. Stargell (2002). SPN1, a conserved gene identified by suppression of a post-recruitment defective yeast TATA-binding protein mutant. Genetics 162, 1605-1616. Yatherajam, G., L. Zhang, S.M. Kraemer, and L.A. Stargell (2003).Protein-protein interaction map for yeast TFIID. Nucleic Acids Research 31:1252-1260. |
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NIH PubMed publications list for Laurie Stargell (This is a link to an external site.) |
Mailing Address: |
| Dept of Biochemistry and Molecular Biology 1870 |
| Colorado State University |
| Fort Collins, CO 80523-1870 |