RNA decay during gammaherpesvirus infection reduces RNA polymerase II occupancy of host promoters but spares viral promoters

Abstract

In mammalian cells, widespread acceleration of cytoplasmic mRNA degradation is linked to impaired RNA polymerase II (Pol II) transcription. This mRNA decay-induced transcriptional repression occurs during infection with gammaherpesviruses including Kaposi's sarcomaassociated herpesvirus (KSHV) and murine gammaherpesvirus 68 (MHV68), which encode an mRNA endonuclease that initiates widespread RNA decay. Here, we show that MHV68induced mRNA decay leads to a genome-wide reduction of Pol II occupancy at mammalian promoters. This reduced Pol II occupancy is accompanied by down-regulation of multiple Pol II subunits and TFIIB in the nucleus of infected cells, as revealed by mass spectrometrybased global measurements of protein abundance. Viral genes, despite the fact that they require Pol II for transcription, escape transcriptional repression. Protection is not governed by viral promoter sequences; instead, location on the viral genome is both necessary and sufficient to escape the transcriptional repression effects of mRNA decay. We propose a model in which the ability to escape from transcriptional repression is linked to the localization of viral DNA within replication compartments, providing a means for these viruses to counteract decay-induced transcript loss. Author summaryWhile transcription and messenger RNA (mRNA) decay are often considered to be the unlinked beginning and end of gene expression, recent data indicate that alterations to either stage can impact the other. Here we study this connection in the context of lytic gammaherpesvirus infection, which accelerates mRNA degradation through the expression of the viral endonuclease muSOX. We show that RNA polymerase II promoter occupancy is broadly reduced across mammalian promoters in response to infection-induced mRNA PLOS Pathogens | https://doi.

Redefining De Novo Gammaherpesvirus Infection Through High-Dimensional, Single-Cell Analysis of Virus and Host

“…Lytic infection is frequently understood as a coordinated cascade of gene expression, characterized by genome-wide transcription (Pellett and Roizman, 2013). High resolution mapping of coding and non-coding viral RNAs (Cheng et al, 2012; O’Grady et al, 2019) and new molecular insights into the regulation of viral RNA transcription and abundance (Hartenian et al, 2020) have further refined models of lytic gene expression. Despite these advances, most studies have analyzed bulk cell populations, obscuring intercellular heterogeneity.…”

Cytoplasmic mRNA decay represses RNA polymerase II transcription during early apoptosis

“…HEK293Ts were made to stably express 633 doxycycline(dox)-inducible wild-type muSOX and its catalytically-dead D219A mutant by 634 PCR amplifying the aforementioned coding sequences from Addgene plasmids 131702 635 and 131704 using the muSOX F/R primers (see Key Resources Table) and InFusion 636 cloning these fragments into the Lenti-X TM Tet-One TM Inducible Expression System 637 digested with AgeI. Lentivirus was made for both constructs by transfecting 293T cells 638 with second generation packaging plasmids and spinfected onto 293T cells at a low 639 multiplicity of infection (MOI) as previously described (Hartenian et al, 2020). 24 hr 640 later, 350 µg/ml zeocin was added to select for transduced cells.…”

Feline calicivirus strain 2280 p30 antagonizes type I interferon-mediated antiviral innate immunity through directly degrading IFNAR1 mRNA

“…In this study, we found that the 5'UTR of IFNAR1 mRNA renders it susceptible to cleavage by 2280 p30 because substitution of the 5'UTR of IFNAR2 mRNA by that of IFNAR1 mRNA conferred susceptibility to 2280 p30-induced mRNA degradation. Variable nucleotide sequences between the 5'UTR of A recent study demonstrated that MHV68-induced mRNA decay during lytic infection also leads to a genome-wide reduction of Pol II occupancy at mammalian promoters, which accelerates host mRNA decay [59]. Whether FCV-induced mRNA decay also contains a similar mechanism need to be further investigated.…”