Mapping cccDNA-Host Interactome Identifies Cohesin Complex as a Novel HBV Restriction Factor

Abstract

Covalently closed circular DNA (cccDNA) of HBV, existing as a stable minichromosome in hepatocyte nucleus, is responsible for persistent HBV infection. Maintainance and sustained replication of cccDNA require its interaction with both viral and proteins. However, cccDNA-interacting host factors limiting its replication remain elusive. Here, by mass-spectrometry based on pull-down with biotinalytaed recombinant cccDNA, called minicircle HBV (MC-HBV), that supports persistent HBV replication and mimics cccDNA minichromosome, we mapped cccDNA-hepatocyte interaction profile, and identified cohesin complex as a cccDNA binding host factor leading to reduced HBV replication. Mechanically, with the help of MAU2-NIPBL complex and CTCF, cohesin loaded on cccDNA and compacted cccDNA to prevent RNAPII enrichment. Interestingly, HBx transcriptionally reduced SMC3 expression to partially relieve the inhibitory role of cohesin complex on HBV replication. In conclusion, our study provides a feasible approach to explore cccDNA-hepatocytes interactome and identifies cohesin complex as a novel HBV restriction factor.