Picorna and Flaviviruses encompass a large variety of medically important human viruses which include those inducing poliomyelitis (poliovirus), infectious (Hep. A) and chronic hepatitis (hepatitis C), common cold (rhinovirus), and myocarditis and encephalitis (coxsackie) among others. A common feature of these viruses is the strategy they employ for synthesis of viral proteins. While cellular mRNAs are translated by cap-dependent """"""""scanning"""""""" mechanism, the viral RNAs are translated by a distinct mechanism involving internal entry of ribosomes within the 5' untranslated region (5' UTR) of viral RNA (IRES-mediated translation). Two inhibitors (a small RNA, IRNA and a small peptide, LAP) which efficiently block hepatitis C and poliovirus IRES-mediated translation (but not cellular translation) both in vivo and in vitro, will be studied. Both biochemical and genetic approaches will be used to determine the mechanism by which IRNA and LAP preferentially inhibit translation of HCV and PV RNAs over cellular mRNAs. Cellular proteins involved in IRES-mediated translation will be purified and their roles in HCV RNA translation will be determined. Structure-function analysis of IRNA will be performed. The mechanism of entry of LAP into hepatocytes will be determined. Identity and normal function of IRNA in the yeast S. cerevisiae will be addressed by cloning and characterizing the IRNA gene. IRNA gene knockout will be performed to better understand the role of IRNA in yeast. We will examine whether IRNA-binding proteins in yeast play any role in IRES-mediated translation (in yeast). Finally, we will develop transgenic mice expressing IRNA and LAP to determine the long term expression of IRNA in animals as well as efficacy of IRNA in blocking virus infections in transgenic animals. It is hoped that the studies proposed here will not only further our understanding of the mechanism of internal initiation of translation in eukaryotic cells, but also provide novel strategies to develop antivirals effective against hepatitis C.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI045733-03
Application #
6374202
Study Section
Experimental Virology Study Section (EVR)
Program Officer
Johnson, Leslye D
Project Start
1999-09-01
Project End
2004-08-31
Budget Start
2001-09-01
Budget End
2002-08-31
Support Year
3
Fiscal Year
2001
Total Cost
$310,352
Indirect Cost
Name
University of California Los Angeles
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
119132785
City
Los Angeles
State
CA
Country
United States
Zip Code
90095
Fontanes, Vanessa; Raychaudhuri, Santanu; Dasgupta, Asim (2009) A cell-permeable peptide inhibits hepatitis C virus replication by sequestering IRES transacting factors. Virology 394:82-90
Raychaudhuri, Santanu; Fontanes, Vanessa; Banerjee, Rajeev et al. (2006) Zuotin, a DnaJ molecular chaperone, stimulates cap-independent translation in yeast. Biochem Biophys Res Commun 350:788-95
Jhaveri, Ravi; Kundu, Pallob; Shapiro, Alan M et al. (2005) Effect of heptitis C virus core protein on cellular gene expression: specific inhibition of cyclooxygenase 2. J Infect Dis 191:1498-506
Izumi, Raquel E; Das, Saumitra; Barat, Bhaswati et al. (2004) A peptide from autoantigen La blocks poliovirus and hepatitis C virus cap-independent translation and reveals a single tyrosine critical for La RNA binding and translation stimulation. J Virol 78:3763-76
Dasgupta, Asim; Das, Saumitra; Izumi, Raquel et al. (2004) Targeting internal ribosome entry site (IRES)-mediated translation to block hepatitis C and other RNA viruses. FEMS Microbiol Lett 234:189-99
Venkatesan, Arun; Sharma, Rakhi; Dasgupta, Asim (2003) Cell cycle regulation of hepatitis C and encephalomyocarditis virus internal ribosome entry site-mediated translation in human embryonic kidney 293 cells. Virus Res 94:85-95
Weidman, Mary K; Sharma, Rahki; Raychaudhuri, Santanu et al. (2003) The interaction of cytoplasmic RNA viruses with the nucleus. Virus Res 95:75-85
Banerjee, R; Dasgupta, A (2001) Interaction of picornavirus 2C polypeptide with the viral negative-strand RNA. J Gen Virol 82:2621-7
Venkatesan, A; Dasgupta, A (2001) Novel fluorescence-based screen to identify small synthetic internal ribosome entry site elements. Mol Cell Biol 21:2826-37
Banerjee, R; Dasgupta, A (2001) Specific interaction of hepatitis C virus protease/helicase NS3 with the 3'-terminal sequences of viral positive- and negative-strand RNA. J Virol 75:1708-21

Showing the most recent 10 out of 11 publications