Table 2.

Characterization of HSV1 UL36 mutants^a

HSV1 strain	Result by the following assay:
	Nuclear egress and assembly					Spread and cell entry
	Nuclear capsids	Capsids in cytoplasm	Capsids with pUl36	Capsids at TGN and gD	Virion assembly	Spread to neighbor cells	Fusion, nuclear VP16	Capsids with pUL36	Plaque formation
wt	+	+	+	+	+	+	+	+	+
ΔUL36	+	+	−	−	−	−	−	−	−
2211stop	+	+	−	−	ND	−	−	−	−
2430stop	+	+	−	−	−	−	−	−	−
2894stop	+	+	+	+	+	+	+	−	−
2998stop	+	+	+	+	+	+	+	−	−

^aThe HSV1 mutants of UL36 characterized in this study can be classified into two groups. In the absence of pUL36 (ΔUL36) or large C-terminal portions (2211stop, 2430 stop), capsids left the nucleus and accumulated in the cytosol, but they no longer recruited pUL36 and did not associate with cytoplasmic membranes. Those mutants lacking only a smaller portion of UL36 (2894stop, 2998stop) recruited the truncated pUL36 forms onto cytosolic capsids, still associated with cytoplasmic membranes, and formed virions that entered neighboring cells. However, the incoming capsids did not contain pUL36, did not bind to the nucleus, and did not initiate viral gene expression. ND, not determined.