5by1
H18 Bat Influenza NS1 RNA Binding Domain
Structural highlights
FunctionU5N1D7_9INFA Inhibits post-transcriptional processing of cellular pre-mRNA, by binding and inhibiting two cellular proteins that are required for the 3'-end processing of cellular pre-mRNAs: the 30 kDa cleavage and polyadenylation specificity factor (CPSF4) and the poly(A)-binding protein 2 (PABPN1). This results in the accumulation of unprocessed 3' end pre-mRNAs which can't be exported from the nucleus. Cellular protein synthesis is thereby shut off very early after virus infection. Viral protein synthesis is not affected by the inhibition of the cellular 3' end processing machinery because the poly(A) tails of viral mRNAs are produced by the viral polymerase through a stuttering mechanism (By similarity).[SAAS:SAAS00210185] Prevents the establishment of the cellular antiviral state by inhibiting TRIM25-mediated DDX58 ubiquitination, which normally triggers the antiviral transduction signal that leads to the activation of type I IFN genes by transcription factors like IRF3 and IRF7. Prevents human EIF2AK2/PKR activation, either by binding double-strand RNA, or by interacting directly with EIF2AK2/PKR. This function may be important at the very beginning of the infection, when NS1 is mainly present in the cytoplasm. Also binds poly(A) and U6 snRNA. Suppresses the RNA silencing-based antiviral response in Drosophila cells (By similarity).[SAAS:SAAS00210196] Publication Abstract from PubMedWe demonstrate that novel bat HL17NL10 and HL18NL11 influenza virus NS1 proteins are effective interferon-antagonists, but do not block general host gene expression. Solving the RNA-binding domain structures revealed the canonical NS1 symmetrical homodimer, and RNA-binding required conserved basic residues in this domain. Interferon-antagonism was strictly dependent on RNA-binding, and chimeric bat influenza viruses expressing NS1s defective in this activity were highly attenuated in interferon-competent cells, but not in cells unable to establish antiviral immunity. Novel Bat Influenza Virus NS1 Proteins Bind Double-Stranded RNA and Antagonize Host Innate Immunity.,Turkington HL, Juozapaitis M, Kerry PS, Aydillo T, Ayllon J, Garcia-Sastre A, Schwemmle M, Hale BG J Virol. 2015 Aug 5. pii: JVI.01430-15. PMID:26246567[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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