Cohesin promotes HSV-1 lytic transcription by facilitating the binding of RNA Pol II on viral genes

Xin Li,Guijun Chen,Nigel W Fraser,Liping Yang,Fengchao Lang,Yafen Yu,Zhuoran Li,Xia Cao,Jumin Zhou,Lihong Li,Erlin Wang

doi:10.1186/s12985-021-01495-2

Abstract

BackgroundHerpes Simplex Virus type I (HSV-1) is a large double-stranded DNA virus that enters productive infection in epithelial cells and reorganizes the host nucleus. Cohesin, a major constituent of interphase and mitotic chromosomes comprised of SMC1, SMC3, and SCC1 (Mcd1/Rad21), SCC3 (SA1/SA2), have diverse functions, including sister chromatid cohesion, DNA double-stranded breaks repair, and transcriptional control. Little is known about the role of cohesin in HSV-1 lytic infection.MethodsWe measured the effect on HSV-1 transcription, genome copy number, and viral titer by depleting cohesin components SMC1 or Rad21 using RNAi, followed by immunofluorescence, qPCR, and ChIP experiments to gain insight into cohesin's function in HSV-1 transcription and replication.ResultsHere, we report that cohesion subunits SMC1 and Rad21 are recruited to the lytic HSV-1 replication compartment. The knockdown results in decreased viral transcription, protein expression, and maturation of viral replication compartments. SMC1 and Rad21 knockdown leads to the reduced overall RNA pol II occupancy level but increased RNA pol II ser5 phosphorylation binding on viral genes. Consistent with this, the knockdown increased H3K27me3 modification on these genes.ConclusionsThese results suggest that cohesin facilitates HSV-1 lytic transcription by promoting RNA Pol II transcription activity and preventing chromatin's silencing on the viral genome.

Highlights

Herpes Simplex Virus type I (HSV-1) is a large double-stranded DNA virus that enters productive infection in epithelial cells and reorganizes the host nucleus
We investigated the role of two core cohesin subunits, SMC1 and Rad21, in HSV-1 lytic infection and found that cohesin is recruited to the HSV-1 replication compartment, its knockdown repressed the formation of the replication compartment, suggesting that cohesin promotes the formation of the HSV-1 replication compartment
Cohesin components SMC1, SMC3, and Rad21 are recruited by HSV‐1 replication compartments To determine whether the replicating HSV-1 genomes interact with the Cohesin complex, we first did double immunostaining with antibodies against the viral protein ICP4 to label the viral replication compartments and antibodies against SMC1, SMC3, and Rad21 in human primary fibroblast BJ cells at 6 h post-infection, a time point when HSV-1 replication centers are well organized

Summary

Introduction

Herpes Simplex Virus type I (HSV-1) is a large double-stranded DNA virus that enters productive infection in epithelial cells and reorganizes the host nucleus. The herpes family of DNA viruses can be divided into neurotropic or alpha Herpes viruses such as HSV and VZV, which latently infect sensory neurons, and lymphotropic Herpes viruses including EBV, KSHV, and CMV, which form latent infections in lymphoid cells, Initial Herpes virus infection begins in epithelial cells before transferring to the cell types which are destined to become latently infected [1]. Herpes Simplex Virus type I (HSV-1) is a linear double-stranded DNA virus with a large 152 kb genome, coding about 80 genes. It enters productive infection in epithelial cells and can establish latent infection in ganglia sensory neurons as a non-integrated, nucleosome-associated episome to colonize the host nucleus. The latent Herpes virus genomes are generally considered to be packed into chromatin in similar ways to the host chromatin [8, 9], which are composed of closely packed, modified histones including H3K27me and H3K9me

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