The herpes simplex virus type 1 (HSV-1) capsid protein VP24 (encoded by UL26) was expressed as a GST-fusion protein and used to prepare a group of monoclonal antibodies. These were used to characterize the protein in capsids and virus infected cells and demonstrated that it exists as two polypeptide species. The nature of the relationship between these two species was investigated and found to be associated with disulphide bonding. Under non-reducing conditions a species corresponding to dimers of VP24 was identified in preparations of B capsids, the site of action of the proteinase. Biochemical subcellular fractionation studies suggested that only cleaved forms of UL26 and UL26.5 gene products could be detected in the nucleus of the infected cell at early times post-infection.
