Pocket protein p130/Rb2 is required for efficient herpes simplex virus type 1 gene expression and viral replication.
We have reported previously that herpes simplex virus type 1 (HSV-1) infection disrupts normal progression of the mammalian cell cycle, causing cells to enter a G(1)-like state. Infected cells were characterized by a decline in cyclin-dependent kinase 2 (CDK2) activities, loss of hyperphosphorylated retinoblastoma protein (pRb), accumulation of E2F-pocket protein complexes, and failure to initiate cellular DNA replication. In the present study, we investigated the role of the pocket proteins pRb, p107, and p130 in HSV-1-dependent cell cycle inhibition and cyclin kinase regulation by infecting murine 3T3 cells derived from wild-type (WT) mouse embryos or embryos with deletions of pRb (pRb(-/-)), p107 (p107(-/-)), p130 (p130(-/-)), or both p130 and p107 (p130(-/-)/p107(-/-)). With respect to CDK2 inhibition, viral protein accumulation, viral DNA replication, and progeny virus yield, WT, pRb(-/-), and p107(-/-) cells were essentially identical. In contrast, after infection of p130(-/-) cells, we observed no inhibition of CDK2 activity, a 5- to 6-h delay in accumulation of viral proteins, an impaired ability to form viral DNA replication compartments, and reduced viral DNA synthesis. As a result, progeny virus yield was reduced 2 logs compared to that in WT cells. Notably, p130(-/-)/p107(-/-) double-knockout cells had a virus replication phenotype intermediate between those of the p107(-/-) and p130(-/-) cells. We conclude from these studies that p130 is a key factor in regulating aspects of cell cycle progression, as well as the timely expression of viral genes and replication of viral DNA.
Ehmann
G L
GL
Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, North Carolina 27599-7290, USA.
Burnett
H A
HA
Bachenheimer
S L
SL
D016475:3T3 Cells; D000818:Animals; D042846:CDC2-CDC28 Kinases; D002453:Cell Cycle; D002522:Chlorocebus aethiops; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors; D004261:DNA Replication; D004279:DNA, Viral / Q000096:biosynthesis; D015870:Gene Expression; D018259:Herpesvirus 1, Human / Q000235:genetics / Q000502:physiology*; D006801:Humans; D051379:Mice; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors; D011506:Proteins; D016160:Retinoblastoma Protein / Q000235:genetics / Q000378:metabolism; D050720:Retinoblastoma-Like Protein p107; D050717:Retinoblastoma-Like Protein p130; D014709:Vero Cells; D014764:Viral Proteins / Q000378:metabolism; D014779:Virus Replication
D004279:DNA, Viral; D009687:Nuclear Proteins; D010750:Phosphoproteins; D011506:Proteins; C493844:RBL1 protein, human; C493837:RBL2 protein, human; C489485:Rbl1 protein, mouse; C493838:Rbl2 protein, mouse; D016160:Retinoblastoma Protein; D050720:Retinoblastoma-Like Protein p107; D050717:Retinoblastoma-Like Protein p130; D014764:Viral Proteins; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases; C495894:CDK2 protein, human; C495893:Cdk2 protein, mouse; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases