Co-regulatory activity of hnRNP K and NS1-BP in influenza and human mRNA splicing

• DOI: 10.1038/s41467-018-04779-4
• Publication Date: 2018-06-15T14:51:34Z
• Authors: Matthew G. Thompson; Raquel Muñoz-Moreno; Prasanna Bhat; Renat Roytenberg; John Lindberg; Matthew R. Gazzara; Michael J. Mallory; Ke Zhang; Adolfo García-Sastre; Beatriz M. A. Fon...; Kristen W. Lynch
• Keywords: 0301 basic medicine; Science; RNA Splicing; Q; Nuclear Proteins; RNA-Binding Proteins; Virus Replication; Article; Ribonucleoprotein, U1 Small Nuclear; 3. Good health; Heterogeneous-Nuclear Ribonucleoprotein K; 03 medical and health sciences; Influenza A virus; Influenza, Human; Mutation; RNA Precursors; Humans; RNA, Viral; RNA, Messenger; Transcription Factors

AbstractThree of the eight RNA segments encoded by the influenza A virus (IAV) undergo alternative splicing to generate distinct proteins. Previously, we found that host proteins hnRNP K and NS1-BP regulate IAV M segment splicing, but the mechanistic details were unknown. Here we show NS1-BP and hnRNP K bind M mRNA downstream of the M2 5′ splice site (5′ss). NS1-BP binds most proximal to the 5′ss, partially overlapping the U1 snRNP binding site, while hnRNP K binds further downstream and promotes U1 snRNP recruitment. Mutation of either or both the hnRNP K and NS1-BP-binding sites results in M segment mis-splicing and attenuated IAV replication. Additionally, we show that hnRNP K and NS1-BP regulate host splicing events and that viral infection causes mis-splicing of some of these transcripts. Therefore, our proposed mechanism of hnRNP K/NS1-BP mediated IAV M splicing provides potential targets of antiviral intervention and reveals novel host functions for these proteins.