Polyadenylation and Translational Control

Univ Of Massachusetts Med Sch Worcester, Worcester MA

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Abstract

Principal Investigator/Program Director (Last, first, middle): Richter, Joel, D. RESEARCH &RELATED Other Project Information 1. * Are Human Subjects Involved? m Yes l No 1.a. If YES to Human Subjects Is the IRB review Pending? m Yes m No IRB Approval Date: Exemption Number: 1 2 3 4 5 6 Human Subject Assurance Number 2. * Are Vertebrate Animals Used? l Yes m No 2.a. If YES to Vertebrate Animals Is the IACUC review Pending? l Yes m No IACUC Approval Date: Animal Welfare Assurance Number A-3306-01 3. * Is proprietary/privileged information m Yes l No included in the application? 4.a.* Does this project have an actual or potential impact on m Yes l No the environment? 4.b. If yes, please explain: 4.c. If this project has an actual or potential impact on the environment, has an exemption been authorized or an environmental assessment (EA) or environmental impact statement (EIS) been performed? m Yes m No 4.d. If yes, please explain: 5.a.* Does this project involve activities outside the U.S. or m Yes l No partnership with International Collaborators? 5.b. If yes, identify countries: 5.c. Optional Explanation: 6. * Project Summary/Abstract Abstract1002193247.pdf Mime Type: application/pdf 7. * Project Narrative ProjectNarrative1002193248.pdf Mime Type: application/pdf 8. Bibliography &References Cited Bibliography1002208475.pdf Mime Type: application/pdf 9. Facilities &Other Resources Facilities1002193245.pdf Mime Type: application/pdf 10. Equipment Equipment1002193246.pdf Mime Type: application/pdf Tracking Number: Other Information Page 5 OMB Number: 4040-0001 Expiration Date: 04/30/2008 Principal Investigator/Program Director (Last, first, middle): Richter, Joel, D. The major objective of this proposal is to understand the molecular mechanisms that control gene expression at the posttranscriptional level in early vertebrate development. In particular, Xenopus oocytes contain many dormant mRNAs that become translated when the cells re-enter the meiotic divisions (oocyte maturation). While dormant, the poly(A) tails on these mRNAs are short;translation ensues when the tails lengthen in response to hormonal stimulation. CPEB is a cytoplasmic polyadenylation element (CPE) specific RNA binding protein that controls poly(A) tail length;it does so in conjunction with several other proteins including CPSF, symplekin, Gld2 (a poly(A) polymerase), and PARN (a deadenylase). While CPE-containing pre-mRNAs acquire a typical long poly(A) tail in the nucleus, the tail is removed once the RNA is exported to the cytoplasm. There, CPEB, Gld2, PARN, and other factors associate with the RNA; Gld2 and PARN are both active, but because PARN is more active, the poly(A) tail is removed. Upon hormonal stimulation, a cascade of events leads to CPEB phosphorylation, an event that expels PARN from the ribonucleoprotein (RNP) complex and allows Gld2-catalyzed default poly(A) tail growth. Polyadenylation controls translation through Maskin, a CPEB binding protein. When the poly(A) tail is short, Maskin is also bound to eIF4E and translation is repressed;an elongated poly(A) tail induces Maskin dissociation from eIF4E, allowing translation to proceed. How the elongated poly(A) tail causes Maskin-eIF4E dissociation will be investigated particularly as it relates to the dynamic change in the factors associated with the CPEB-containing RNP complex during oocyte maturation. Recent experiments have shown that CPEB transiently resides in the nucleus where it interacts with CPE-containing pre-mRNA as well as several processing factors. We will determine whether CPEB is involved in nuclear RNA processing and whether its nuclear experience determines the cytoplasmic fate of mRNA. Finally, an upstream event that is necessary for CPEB-mediated polyadenylation is the translational activation of RINGO/Spy mRNA, which encodes an atypical cyclin B1-like protein. Pumilio is the