BIOCHEMISTRY

Scott Ballantyne

B.S. University of Wisconsin - Parkside, Biology
PhD. University of Wisconsin - Madison, Biochemistry

scott.m.ballantyne@uwrf.edu

My research focuses on the poly(A) tail present at the 3’ end of most mRNAs. I am particularly interested in how cells can selectively lengthen or shorten these tails in response to various environmental or developmental cues. Changes in poly(A) tail length can influence the translation and stability of an mRNA, and so provide a means of controlling gene expression after transcription. During my graduate work I used frog eggs as a model system to establish links between cytoplasmic polyadenylation and cell cycle control (See papers 3 & 4 below). My current work centers on how a particular 3’UTR regulator, GLD-1, can promote poly(A) shorterning and translational repression. Using a yeast two-hybrid screen I discovered that GLD-1 binds to the poly(A) binding protein (PAB) that normally occupies the poly(A) tail. I am now performing a combination of in vitro and in vivo experiments to determine whether this interaction is required for the ability of GLD-1 to reduce poly(A) tail length and mRNA translation.

A long-term goal of my research is to identify connections between poly(A) tail metabolism, mRNA regulation, and other metabolic processes. Such links are often missed by traditional biochemical approaches. For example, biochemical purification identified proteins that collectively seemed to reconstitute nuclear polyadenylation fully in the test tube. However, in living cells, the same reaction is intimately linked to splicing and transcription(See paper 2 below). Indeed, it now appears that mRNA biogenesis in the nucleus, including polyadenylation, is carried out by an emormous protein complex, with multiple catalytic activities. Are molecular machines of such complexity responsible for cytoplasmic poly(A) tail changes? What other cellular processes are linked to the addition and removal of poly(A)? Answers to holistic questions like these are required for our full understanding of the biology behind these biochemical reactions.

Publications

1. Robert Freeman, John Kanki, Scott Ballantyne, Katherine Pickham, and Daniel Donoghue. 1990. Effects of the v-mos oncogene on Xenopus development: meiotic induction in oocytes and mitotic arrest in cleaving embryos. J. Cell Biol. 111: 533-541. [PubMed]
2. Robert Freeman, Scott Ballantyne, and Daniel Donoghue. 1991. Meiotic induction by Xenopus cyclin B is accelerated by coexpression with c-mos. Mol. Cell. Biol. 11: 1713-1717. [PubMed]
3. Scott Ballantyne, Andrea Bilger, Jonas Astrom, Anders Virtanen, and Marvin Wickens. 1995. Poly(A) polymerases in the nucleus and cytoplasm of frog oocytes: dynamic changes during oocyte maturation and early development. RNA 1: 64-78. [PubMed]
4. Susan McCracken, Nova Fong, Krassimir Yankulov, Scott Ballantyne, Guohua Pan, Jack Greenblatt, Scott Patterson, Marvin Wickens, and David Bentley. 1997. The C-terminal domain of RNA polymerase II couples mRNA processing to transcription. Nature 385: 357-361. [PubMed]
5. Scott Ballantyne, Donald L. Daniel, Jr., and Marvin Wickens. 1997. A dependent pathway of cytoplasmic polyadenylation reactions linked to cell cycle control by c-mos and CDK1 activation. Mol. Biol. Cell 8: 1633-1648. [PubMed]
6. Aaron Barkoff, Scott Ballantyne, and Marvin Wickens. 1998. Meiotic maturation in Xenopus requires polyadenylation of multiple mRNAs. EMBO J. 17: 3168-3175. [PDF] [PubMed]
7. Kris Dickson, Andrea Bilger, Scott Ballantyne, and Marvin Wickens 1999. The cleavage and polyadenylation specificity factor in Xenopus laevis oocytes is a cytoplasmic factor involved in regulated polyadenylation. Mol Cell Biol. 19(8): 5707-17. [PDF] [PubMed]
8. Scott Ballantyne, Eric Jang, Marvin Wickens, and Elizabeth Goodwin (in prep.). GLD-1 represses translation of tra-2 mRNA in a poly(A) tail dependent manner and binds to PAB.