Inhibition of endocytic pathways impacts cytomegalovirus maturation

Sci Rep. 2017 Apr 13:7:46069. doi: 10.1038/srep46069.

Abstract

Endocytic processes are critical for cellular entry of several viruses; however, the role of endocytosis in cellular trafficking of viruses beyond virus entry is only partially understood. Here, we utilized two laboratory strains (AD169 and Towne) of human cytomegalovirus (HCMV), which are known to use cell membrane fusion rather than endocytosis to enter fibroblasts, in order to study a post-entry role of endocytosis in HCMV life cycle. Upon pharmacological inhibition of dynamin-2 or clathrin terminal domain (TD) ligand association, these strains entered the cells successfully based on the expression of immediate early viral protein. However, both the inhibitors significantly reduced the growth rates and final virus yields of viruses without inhibiting the expression of early to late viral proteins. Clathrin accumulated in the cytoplasmic virus assembly compartment (vAC) of infected cells co-localizing with virus tegument protein pp150 and the formation of vAC was compromised upon endocytic inhibition. Transmission electron micrographs (TEM) of infected cells treated with endocytosis inhibitors showed intact nuclear stages of nucleocapsid assembly but the cytoplasmic virus maturation was greatly compromised. Thus, the data presented here implicate endocytic pathways in HCMV maturation and egress.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biomarkers / metabolism
  • Cell Survival / drug effects
  • Cells, Cultured
  • Clathrin / metabolism
  • Cytomegalovirus / drug effects
  • Cytomegalovirus / growth & development
  • Cytomegalovirus / physiology*
  • Dynamins / metabolism
  • Endocytosis* / drug effects
  • Fibroblasts / drug effects
  • Fibroblasts / metabolism
  • Fibroblasts / ultrastructure
  • Fibroblasts / virology
  • Green Fluorescent Proteins / metabolism
  • Humans
  • Hydrazones / pharmacology
  • Sulfonamides / pharmacology
  • Thiazolidines / pharmacology
  • Viral Proteins / metabolism
  • Virus Internalization / drug effects
  • Virus Replication / drug effects

Substances

  • Biomarkers
  • Clathrin
  • Hydrazones
  • N'-(3,4-dihydroxybenzylidene)-3-hydroxy-2-naphthahydrazide
  • Sulfonamides
  • Thiazolidines
  • Viral Proteins
  • pitstop 2
  • Green Fluorescent Proteins
  • Dynamins