Leader RNA binding ability of Chandipura virus P protein is regulated by its phosphorylation status: a possible role in genome transcription-replication switch.
The molecular events associated with the transcriptive and replicative cycle of negative-stranded RNA viruses are still an enigma. We took Chandipura virus, a member of the Rhabdoviridae family, as our model system to demonstrate that Phosphoprotein P, besides Nucleocapsid protein N, also acts as a leader RNA-binding protein in its unphosphorylated form, whereas CKII-mediated phosphorylation totally abrogates its RNA-binding ability. However, interaction between P protein and leader RNA can be distinguished from N-mediated encapsidation of viral sequences. Furthermore, P protein bound to leader chain can successively recruit N protein on RNA while itself being replaced. We also observed that the accumulation of phosphorylation null mutant of P protein in cells results in enhanced genome RNA replication with concurrent increase in the viral yield. All these results led us to propose a model explaining viral transcription-replication switch where Phosphoprotein P acts as a modulator of genome transcription and replication by its ability to bind to the nascent leader RNA in its unphosphorylated form, promoting read-through of the transcription termination signals and initiating nucleocapsid assembly on the nascent RNA chain.
Basak
Soumen
S
Dr. B.C. Guha Centre for Genetic Engineering and Biotechnology, Department of Biochemistry, Calcutta University, Kolkata, India.
Raha
Tamal
T
Chattopadhyay
Debasish
D
Majumder
Amitabha
A
Shaila
M S
MS
Chattopadhyay
D J
DJ
D020121:5' Untranslated Regions / Q000378:metabolism*; D000818:Animals; D001483:Base Sequence; D006224:Cricetinae; D016679:Genome, Viral; D018832:Molecular Chaperones; D008969:Molecular Sequence Data; D019590:Nucleocapsid Proteins / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D012367:RNA, Viral / Q000378:metabolism*; D014158:Transcription, Genetic; D015678:Viral Structural Proteins / Q000378:metabolism*; D014779:Virus Replication
D020121:5' Untranslated Regions; D018832:Molecular Chaperones; D019590:Nucleocapsid Proteins; C412837:P protein, Chandipura virus; D010750:Phosphoproteins; D012367:RNA, Viral; D015678:Viral Structural Proteins