Induction of a host-specific chromatin-associated glycopolypeptide by human cytomegalovirus

Analysis of chromatin preparations from [3H]glucosamine-labelled human foreskin fibroblasts revealed that a chromatin-associated glycopolypeptide with the approximate mol. wt. 130 000 (130K) is induced in response to either infection with human cytomegalovirus (HCMV) or serum treatment. Comparative limited proteolysis suggested that the [3H]glucosamine-labelled 130K polypeptides induced by these different stimuli were not identical. This observation was in contrast to results obtained by immunoprecipitation with antisera raised against the 130K glycopolypeptide from serum-induced cells which favoured a relatedness to the 130K polypeptide from virus-infected cultures. Two-dimensional separation by isoelectric focusing and SDS-polyacrylamide gel electrophoresis subsequently showed that the 130K glycopolypeptide from serum-induced cells consists of two components, one of which is identical to the single component observed in samples from HCMV-infected cultures. Experiments on the effect of glycosylation inhibitors on DNA replication in HCMV-infected as well as in serum-induced cells support the view that the host-specific chromatin-associated glycopolypeptide may be involved in DNA replication in infected cells.