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Identification of specific structural element in the leader RNA of Chandipura virus and its implication in Phosphoprotein recognition
Author(s) -
Polley Smarajit,
Chattopadhyay Dhrubajyoti,
Roy Siddhartha
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a930-a
Subject(s) - rna , phosphoprotein , dimer , rna dependent rna polymerase , transcription (linguistics) , viral replication , chemistry , biology , microbiology and biotechnology , polymerase , virus , virology , biochemistry , phosphorylation , gene , linguistics , philosophy , organic chemistry
Chandipura virus (CHPV) belongs to the mononegaloviridae family consisting of a nonsegmented RNA genome, tolling hundreds of children in India during 2002–05. Most crucial event in the life cycle of CHPV is the Transcription‐Replication Switch; both being carried out by the same viral Polymerase, L. Viral Phosphoprotein phosphorylated at Ser62 (P 1 ) is essential for Transcriptase activity of L whereas the unphosphorylated one (P 0 ) promotes replication. 49‐mer viral leader RNA (CHPl), transcribed from 3′‐end of the genome, forms two complexes with P 0 with nanomolar K d , depending upon the protein concentration but fails to recognize P 1 . Here, we show by Dynamic Light Scattering that, P 0 undergoes monomer to dimer to higher oligomer formation with increasing protein concentration. The 5′‐terminal half of CHPl binds preferentially with the dimer of P 0 whereas 3′‐half interacts preferentially with the monomeric form as revealed by Tryptophan fluorescence quenching studies. NMR spectroscopic studies of CHPl and structure prediction suggest the presence of a stem‐loop structure at the 3′‐end of the RNA. Temperature dependence of 1 H‐1D NMR spectra confirms that CHPl contains a core structure that is stable at least up to 50°C. Effect of Mg 2+ on folding of the RNA is also studied. Point mutants in the predicted stem‐loop of CHPl indicate the role of different bases in recognizing P 0 as evidenced by competitive RNA binding experiments using Gel Retardation Assay. Screening molecules to block this interaction may lead to antiviral agents. DST and CSIR, INDIA supported this study.