Paramjit Khurana

Friday Seminar by Ms. Kamlesh Kumari

IDG Lab/ Friday/ January 11, 2019/ 3.30 pm/  Cytoplasmic Viruses : Rage Against the Machine
Category: Research
Posted by: bedineel

Cytoplasmic Viruses: Rage Against The Machine

Kamlesh Kumari

The cellular RNA decay machinery constantly monitors transcripts, from the time they are synthesized in the nucleus until the end of their lifespan in the cytoplasm. Aberrant products of transcription initiation (e.g. PROMPTS), capping, and termination are quickly degraded by nuclear RNA quality control surveillance complexes. Rapid RNA virus evolution is a major problem due to the devastating diseases caused by human, animal and plant-pathogenic RNA viruses. When the transcripts of cytoplasmic viruses are generated, they must actively avoid or overcome the assault by these aggressive cellular mRNA decay complexes in order to be translated and effectively generate virions. Picornaviruses use an aggressive mechanism for suppression of host RNA decay factors. Xrn1, Dcp1, Dcp2, Pan3 (a deadenylase), and AUF1 (a factor that targets RNAs for decay) are rapidly degraded during poliovirus or human rhinovirus infections by viral proteases or the host cell proteasome. The dispersal of P-bodies (cytoplasmic aggregates of host RNA decay factors) in several viral infections is also evidence of disruption of cellular RNA decay activities. Several RNA decay components have been suggested to attenuate RNA silencing possibly through competing for RNA substrates. Taken together, this data highlight the overlapping function of the RNA silencing and RNA decay pathways in plants, as evidenced by their hierarchical and concerted actions against exogenous and viral RNA, and VSRs not only counteract RNA silencing but also subvert RNA decay to promote viral infection.