Messenger RNA (mRNA) translation initiation in eucaryotic cells requires the concerted action of several different pathways. For instance, ribosomal subunits must be kept dissociated in the absence of mRNA, and mRNA must be packaged into a form that will be recognized by the ribosomal subunits. The first step in translation initiation is the 5' to 3' directional scanning of the 40S ribosomal subunit on the mRNA until it binds to the initiator codon. The second step is the joining of the 60S ribosomal subunit to form the monoribosome. The goal of this proposal is to understand the mechanism and regulation of the 60S ribosomal subunit joining step in yeast, and more generally to understand mRNA recognition in eucaryotic cells. Past work suggests that the 60S subunit joining step requires the poly(A) tail on mRNA. Recently the poly(A) ribonuclease (PAN) has been implicated as a mediator of this requirement. The experiments described here outline how PAN's role in translation will be studied in vitro using PAN-dependent translation extracts. They will explore PAN's association with the ribosome and determine if mutations in PAN or in other proteins interacting with PAN effect it. They will define the importance of PAN phosphorylation and of its associated kinase in the translation pathways. Finally, the characterization of pan1 mutant phenotypes, and of extragenic suppressors and synthetic lethal mutations with PAN, will be pursued to gain more insight into PAN's function in vivo. The results of this work may provide a more detailed understanding of a fundamental reaction in eucaryotic cells. The results obtained may pave the way for future work exploring alterations of this pathways during cellular transformation or infection.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM050308-02
Application #
2188049
Study Section
Molecular Biology Study Section (MBY)
Project Start
1994-09-01
Project End
1998-08-31
Budget Start
1995-09-01
Budget End
1996-08-31
Support Year
2
Fiscal Year
1995
Total Cost
Indirect Cost
Name
University of California Berkeley
Department
Biochemistry
Type
Schools of Arts and Sciences
DUNS #
094878337
City
Berkeley
State
CA
Country
United States
Zip Code
94704
Holmes, L E A; Campbell, S G; De Long, S K et al. (2004) Loss of translational control in yeast compromised for the major mRNA decay pathway. Mol Cell Biol 24:2998-3010
Inada, Toshifumi; Winstall, Eric; Tarun Jr, Salvador Z et al. (2002) One-step affinity purification of the yeast ribosome and its associated proteins and mRNAs. RNA 8:948-58
Ashe, M P; Slaven, J W; De Long, S K et al. (2001) A novel eIF2B-dependent mechanism of translational control in yeast as a response to fusel alcohols. EMBO J 20:6464-74
Winstall, E; Sadowski, M; Kuhn, U et al. (2000) The Saccharomyces cerevisiae RNA-binding protein Rbp29 functions in cytoplasmic mRNA metabolism. J Biol Chem 275:21817-26
Fortes, P; Inada, T; Preiss, T et al. (2000) The yeast nuclear cap binding complex can interact with translation factor eIF4G and mediate translation initiation. Mol Cell 6:191-6
Ashe, M P; De Long, S K; Sachs, A B (2000) Glucose depletion rapidly inhibits translation initiation in yeast. Mol Biol Cell 11:833-48
Morrissey, J P; Deardorff, J A; Hebron, C et al. (1999) Decapping of stabilized, polyadenylated mRNA in yeast pab1 mutants. Yeast 15:687-702
Tarun Jr, S Z; Sachs, A B (1997) Binding of eukaryotic translation initiation factor 4E (eIF4E) to eIF4G represses translation of uncapped mRNA. Mol Cell Biol 17:6876-86
Deardorff, J A; Sachs, A B (1997) Differential effects of aromatic and charged residue substitutions in the RNA binding domains of the yeast poly(A)-binding protein. J Mol Biol 269:67-81
Tarun Jr, S Z; Sachs, A B (1996) Association of the yeast poly(A) tail binding protein with translation initiation factor eIF-4G. EMBO J 15:7168-77

Showing the most recent 10 out of 13 publications