Remove of introns from messenger RNA precursors (pre-mRNA) is an essential process in eukaryotic gene expression. To remove introns, a large RNA-protein complex, known as the spliceosome, must be assembled on pre-mRNA through an ordered multi-step pathway. Although an outline picture of how pre-mRNA is spliced has emerged from the numerous studies, many important knowledge gaps remain. Among the many interesting unanswered questions, the roles of so-called DExH/D box helicase proteins in the spliceosome are particularly intriguing. A number of putative RNA helicases have been shown to function in the spliceosome. However, our knowledge that links a putative helicase to a specific target RNA duplex is currently limited. The goal of this proposal is to understand the biological functions of the p68 RNA helicase that was recently detected interacting with the transient U1:5'ss duplex during the spliceosome assembly (Liu, 1998). Our preliminary data suggest that the p68 RNA helicase is essential for in vitro pre-mRNA splicing. The protein may be functionally involved in mediating the U1 snRNA and pre-mRNA interactions during the spliceosome assembly. P68 may also plays a role in the process of addition of U5.U4/U6 tri-snRNP to the pre-spliceosome. This proposal will investigate the functional roles of p68 RNA helicase in the pre-mRNA splicing process. The studies will focus on two important issues: (1) Does p68 RNA helicase unwind the U1:5'ss duplex. (2) Does p68 plays a role in the addition of the tri-snRNP. We anticipate that understanding the functional roles of p68 would constitute a significant advance in knowledge about the mechanism of the spliceosome assembly. In the process of characterization of enzymatic activity of p68 helicase, we first demonstrated dsRNA-binding and dsRNA stimulated ATPase activity. We propose experiments to elucidate the RNA-binding mechanism and investigate how the RNA-binding is coupled to the enzymatic activities of p68.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM063874-04
Application #
6878085
Study Section
Cell Development and Function Integrated Review Group (CDF)
Program Officer
Rhoades, Marcus M
Project Start
2003-05-01
Project End
2008-04-30
Budget Start
2005-05-01
Budget End
2006-04-30
Support Year
4
Fiscal Year
2005
Total Cost
$216,431
Indirect Cost
Name
Georgia State University
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
837322494
City
Atlanta
State
GA
Country
United States
Zip Code
30302
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Wang, Haizhen; Gao, Xueliang; Huang, Yun et al. (2009) P68 RNA helicase is a nucleocytoplasmic shuttling protein. Cell Res 19:1388-400
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Yang, L; Lin, C; Sun, S-Y et al. (2007) A double tyrosine phosphorylation of P68 RNA helicase confers resistance to TRAIL-induced apoptosis. Oncogene 26:6082-92
Yang, Liuqing; Lin, Chunru; Zhao, Shumin et al. (2007) Phosphorylation of p68 RNA helicase plays a role in platelet-derived growth factor-induced cell proliferation by up-regulating cyclin D1 and c-Myc expression. J Biol Chem 282:16811-9
Wang, Haizhen; Liu, Yongding; Gao, Xueliang et al. (2007) The recombinant beta subunit of C-phycocyanin inhibits cell proliferation and induces apoptosis. Cancer Lett 247:150-8
Yang, Liuqing; Lin, Chunru; Liu, Zhi-Ren (2006) P68 RNA helicase mediates PDGF-induced epithelial mesenchymal transition by displacing Axin from beta-catenin. Cell 127:139-55
Yang, Liuqing; Lin, Chunru; Liu, Zhi-Ren (2005) Signaling to the DEAD box--regulation of DEAD-box p68 RNA helicase by protein phosphorylations. Cell Signal 17:1495-504

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