The herpes simplex virus 1 (HSV-1) genome encodes seven polypeptides that are required for its replication. These include a heterodimeric DNA polymerase, a singlestrand-DNA-binding protein, a heterotrimeric helicase/primase, and a protein (UL9 protein) that binds specifically to an HSV-1 origin of replication (oris). We demonstrate here that UL9 protein interacts specifically with the 180-kDa catalytic subunit of the cellular DNA polymerase a-primase. This interaction can be detected by immunoprecipitation with antibodies directed against either of these proteins, by gel mobility shift of an oris-UL9 protein complex, and by stimulation of DNA polymerase activity by the UL9 protein. These findings suggest that enzymes required for cellular DNA replication also participate in HSV-1 DNA replication.In vivo studies of the replication of the linear 152-kb herpes simplex virus 1 (HSV-1) genome have demonstrated that it circularizes shortly after infection and then enters a rolling circle mode of DNA replication (1). However, the existence of three origins of replication, OriL and the diploid oris, as well as an HSV-1-encoded protein (UL9 protein) that binds specifically to these origins (for review, see ref.2), suggests that origin-dependent, theta-type DNA replication, analogous to that observed for the simian virus 40 (SV40) minichromosome, may also occur. A recent analysis in vivo of the replication of plasmids containing an HSV-1 origin (oris) in HSV-1-infected cells by two-dimensional gel analysis (3) has identified "bubble arcs" indicative of theta-type DNA replication (K. Kelly and I.R.L., unpublished data).The HSV-1 genome encodes seven polypeptides that are essential for its replication (2, 4). These include, in addition to the UL9 protein, a heterodimeric, highly processive DNA polymerase, a single-strand-DNA-binding protein (ICP8), and a heterotrimeric helicase/primase. We have recently found that a complex consisting of the HSV-1 DNA polymerase, helicase/primase, and ICP8, isolated from Sf21 insect cells multiply infected with baculoviruses recombinant for the genes encoding these enzymes, can promote the rolling circle replication of a 3-kb plasmid that is independent of oris and the UL9 protein (5). This reaction may reflect the rolling circle phase of viral DNA replication.The UL9 protein, which exists in solution as a homodimer of 83-kDa subunits (6, 7), binds to specific sequences within onts (sites I, II, and III) (8-11). The two high-affinity sites (sites I and II) are separated by an 18-nt A+T-rich spacer. The UL9 protein also has DNA-dependent ATPase and DNA helicase activities (6,7,12,13 Studies of SV40 DNA replication in vitro have shown that the SV40 T antigen interacts specifically with the cellular DNA polymerase a-primase (Pol a) to form a complex that initiates DNA replication at the SV40 origin (16-19). We have therefore inquired whether the HSV-1-encoded UL9 protein forms an analogous complex with Pol a. We demonstrate here that the UL9 protein interacts specifically with the cata...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.