Abstract
Because several studies have shown that exogenous miR-199a has antiviral effects against various viruses, including herpesviruses, we examined how miR-199a exerts its antiviral effects using epithelial tumour cell lines infected with herpes simplex virus-1 (HSV-1). We found that both miR-199a-5p and -3p impair the secondary envelopment of HSV-1 by suppressing their common target, ARHGAP21, a Golgi-localized GTPase-activating protein for Cdc42. We further found that the trans-cisternae of the Golgi apparatus are a potential membrane compartment for secondary envelopment. Exogenous expression of either pre-miR-199a or sh-ARHGAP21 exhibited shared phenotypes i.e. alteration of Golgi function in uninfected cells, inhibition of HSV-1 secondary envelopment, and reduction of trans-Golgi proteins upon HSV-1 infection. A constitutively active form of Cdc42 also inhibited HSV-1 secondary envelopment. Endogenous levels of miR-199a in epithelial tumour cell lines were negatively correlated with the efficiency of HSV-1 secondary envelopment within these cells. These results suggest that miR-199a is a crucial regulator of Cdc42 activity on Golgi membranes, which is important for the maintenance of Golgi function and for the secondary envelopment of HSV-1 upon its infection.
Highlights
Because several studies have shown that exogenous miR-199a has antiviral effects against various viruses, including herpesviruses, we examined how miR-199a exerts its antiviral effects using epithelial tumour cell lines infected with herpes simplex virus-1 (HSV-1)
The miR-199a/miR-214 locus, from which the transcript is processed into miR-199a-5p, miR199a-3p, and miR-214, is a good model for studying the function of host miRNAs in viral replication because several previous studies have described the antiviral effects of miR-199a-3p and miR-214 against herpesviruses, Semliki Forest virus[1], hepatitis C virus (HCV)[2], and hepatitis B virus[3], raising the possibility that these miRNAs target host factor(s) that are critically involved in the replication of many types of virus
Of the 21 selected candidate genes, we focused on ARHGAP21 because it was predicted to be a good target of both miR-199a-5p and -3p (Fig. 3A) and because it has been reported to be important for Golgi function; ARHGAP21 is a Cdc42-specific GTPase-activating protein (GAP) that can bind to ARF1, which reportedly recruits ARHGAP21 to the Golgi apparatus[25, 26]
Summary
Because several studies have shown that exogenous miR-199a has antiviral effects against various viruses, including herpesviruses, we examined how miR-199a exerts its antiviral effects using epithelial tumour cell lines infected with herpes simplex virus-1 (HSV-1) We found that both miR-199a-5p and -3p impair the secondary envelopment of HSV-1 by suppressing their common target, ARHGAP21, a Golgi-localized GTPase-activating protein for Cdc[42]. Through a cascade of HSV-1 gene expression phases (immediate early genes, early genes, and late genes), genomic DNA is replicated and packaged into capsids in the nucleus These capsids are enveloped at the inner nuclear membrane and bud into the space between the inner and outer nuclear membrane, a process known as primary envelopment. Infectious virions inside the compartments are transported to the extracellular space[10, 11]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
