Autophagy and the effects of its inhibition or induction were investigated 
during the entire infectious cycle of varicella-zoster virus (VZV), a human 
herpesvirus. As a baseline, we first enumerated the number of autophagosomes per 
cell after VZV infection compared with the number after induction of autophagy 
following serum starvation or treatment with tunicamycin or trehalose. Punctum 
induction by VZV was similar in degree to punctum induction by trehalose in 
uninfected cells. Treatment of infected cells with the autophagy inhibitor 
3-methyladenine (3-MA) markedly reduced the viral titer, as determined by assays 
measuring both cell-free virus and infectious foci (P < 0.0001). We next 
examined a virion-enriched band purified by density gradient sedimentation and 
observed that treatment with 3-MA decreased the amount of VZV gE, while 
treatment with trehalose increased the amount of gE in the same band. Because 
VZV gE is the most abundant glycoprotein, we selected gE as a representative 
viral glycoprotein. To further investigate the role of autophagy in VZV 
glycoprotein biosynthesis as well as confirm the results obtained with 3-MA 
inhibition, we transfected cells with ATG5 small interfering RNA to block 
autophagosome formation. VZV-induced syncytium formation was markedly reduced by 
ATG5 knockdown (P < 0.0001). Further, we found that both expression and glycan 
processing of VZV gE were decreased after ATG5 knockdown, while expression of 
the nonglycosylated IE62 tegument protein was unchanged. Taken together, our 
cumulative results not only documented abundant autophagy within VZV-infected 
cells throughout the infectious cycle but also demonstrated that VZV-induced 
autophagy facilitated VZV glycoprotein biosynthesis and processing.