title: Interaction of chandipura virus N and P proteins: identification of two mutually exclusive domains of N involved in interaction with P.
abstract: The nucleocapsid protein (N) and the phosphoprotein (P) of nonsegmented negative-strand (NNS) RNA viruses interact with each other to accomplish two crucial events necessary for the viral replication cycle. First, the P protein binds to the aggregation prone nascent N molecules maintaining them in a soluble monomeric (N(0)) form (N(0)-P complex). It is this form that is competent for specific encapsidation of the viral genome. Second, the P protein binds to oligomeric N in the nucleoprotein complex (N-RNA-P complex), and thereby facilitates the recruitment of the viral polymerase (L) onto its template. All previous attempts to study these complexes relied on co-expression of the two proteins in diverse systems. In this study, we have characterised these different modes of N-P interaction in detail and for the first time have been able to reconstitute these complexes individually in vitro in the chandipura virus (CHPV), a human pathogenic NNS RNA virus. Using a battery of truncated mutants of the N protein, we have been able to identify two mutually exclusive domains of N involved in differential interaction with the P protein. An unique N-terminal binding site, comprising of amino acids (aa) 1-180 form the N(0)-P interacting region, whereas, C-terminal residues spanning aa 320-390 is instrumental in N-RNA-P interactions. Significantly, the ex-vivo data also supports these observations. Based on these results, we suggest that the P protein acts as N-specific chaperone and thereby partially masking the N-N self-association region, which leads to the specific recognition of viral genome RNA by N(0).
authors.affiliation: Department of Biotechnology and Dr BC Guha Centre for Genetic Engineering and Biotechnology, University of Calcutta, Kolkata, West Bengal, India.
authors.forename: Arindam
authors.initials: A
authors.lastname: Mondal
authors.forename: Arunava
authors.initials: A
authors.lastname: Roy
authors.forename: Sandipto
authors.initials: S
authors.lastname: Sarkar
authors.forename: Jishnu
authors.initials: J
authors.lastname: Mukherjee
authors.forename: Tridib
authors.initials: T
authors.lastname: Ganguly
authors.forename: Dhrubajyoti
authors.initials: D
authors.lastname: Chattopadhyay
mesh_terms: D000818:Animals; D002522:Chlorocebus aethiops; D018832:Molecular Chaperones; D019590:Nucleocapsid Proteins / Q000737:chemistry* / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D010750:Phosphoproteins / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D011993:Recombinant Fusion Proteins / Q000737:chemistry* / Q000378:metabolism; D014709:Vero Cells; D018116:Vesiculovirus; D015678:Viral Structural Proteins / Q000737:chemistry* / Q000378:metabolism
chemical_list: D018832:Molecular Chaperones; D019590:Nucleocapsid Proteins; C412837:P protein, Chandipura virus; D010446:Peptide Fragments; D010750:Phosphoproteins; D011993:Recombinant Fusion Proteins; D015678:Viral Structural Proteins