Herpes simplex virus type 1 abrogates the antiviral activity of Ch25h via its virion host shutoff protein

Cholesterol 25-hydroxylase (Ch25h) is an interferon-inducible protein, and recent studies have demonstrated that it inhibited the replication of many enveloped viruses. However, in this study, we found that cells infected with wild-type (WT) HSV-1 reduced the expression of Ch25h, and ectopic expression of Ch25h could not inhibit the replication of WT-HSV-1. By screening assay, HSV-1 UL41 protein was found to down-regulate the expression of Ch25h. In addition, UL41 abrogated the antiviral activity of Ch25h via degrading its mRNA. Furthermore, ectopic expression of Ch25h inhibited the replication of UL41-null mutant HSV-1 (R2621), but not WT-HSV-1, and knockdown of Ch25h did not affect the replication of WT-HSV-1, but promoted the replication of the R2621. For the first time, HSV-1 UL41 was demonstrated to evade the antiviral function of Ch25h via its endonuclease activity. •UL41 abrogated the antiviral activity of Ch25h via degrading its mRNA.•Ectopic expression of Ch25h inhibited the replication of R2621, but not WT-HSV-1.•Knockdown of endogenous Ch25h did not affect the replication of WT-HSV-1, but promoted the replication of the R2621.