title: Activation of DNA Damage Response Pathways during Lytic Replication of KSHV.
abstract: Kaposi's sarcoma-associated herpesvirus (KSHV) is the causative agent of several human malignancies. Human tumour viruses such as KSHV are known to interact with the DNA damage response (DDR), the molecular pathways that recognise and repair lesions in cellular DNA. Here it is demonstrated that lytic reactivation of KSHV leads to activation of the ATM and DNA-PK DDR kinases resulting in phosphorylation of multiple downstream substrates. Inhibition of ATM results in the reduction of overall levels of viral replication while inhibition of DNA-PK increases activation of ATM and leads to earlier viral release. There is no activation of the ATR-CHK1 pathway following lytic replication and CHK1 phosphorylation is inhibited at later times during the lytic cycle. Despite evidence of double-strand breaks and phosphorylation of H2AX, 53BP1 foci are not consistently observed in cells containing lytic virus although RPA32 and MRE11 localise to sites of viral DNA synthesis. Activation of the DDR following KSHV lytic reactivation does not result in a G1 cell cycle block and cells are able to proceed to S-phase during the lytic cycle. KSHV appears then to selectively activate DDR pathways, modulate cell cycle progression and recruit DDR proteins to sites of viral replication during the lytic cycle.
authors.affiliation: School of Cancer Sciences, the College of Medicine and Dentistry, University of Birmingham, Birmingham B15 2TT, UK. rxh291@student.bham.ac.uk.
authors.forename: Robert
authors.initials: R
authors.lastname: Hollingworth
authors.affiliation: School of Cancer Sciences, the College of Medicine and Dentistry, University of Birmingham, Birmingham B15 2TT, UK. g.s.stewart@bham.ac.uk.
authors.forename: George L
authors.initials: GL
authors.lastname: Skalka
authors.affiliation: School of Cancer Sciences, the College of Medicine and Dentistry, University of Birmingham, Birmingham B15 2TT, UK. g.s.stewart@bham.ac.uk.
authors.forename: Grant S
authors.initials: GS
authors.lastname: Stewart
authors.affiliation: School of Cancer Sciences, the College of Medicine and Dentistry, University of Birmingham, Birmingham B15 2TT, UK. a.d.hislop@bham.ac.uk.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Hislop
authors.affiliation: School of Biosciences and Medicine, University of Surrey, Surrey GU2 7XH, UK. d.blackbourn@surrey.ac.uk.
authors.forename: David J
authors.initials: DJ
authors.lastname: Blackbourn
authors.affiliation: School of Cancer Sciences, the College of Medicine and Dentistry, University of Birmingham, Birmingham B15 2TT, UK. r.j.a.grand@bham.ac.uk.
authors.forename: Roger J
authors.initials: RJ
authors.lastname: Grand
mesh_terms: D064007:Ataxia Telangiectasia Mutated Proteins / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002453:Cell Cycle; D002460:Cell Line; D004249:DNA Damage; D004260:DNA Repair; D019288:Herpesvirus 8, Human / Q000502:physiology*; D054884:Host-Pathogen Interactions; D006801:Humans; D014775:Virus Activation; D014779:Virus Replication
chemical_list: C109198:CIB1 protein, human; D002135:Calcium-Binding Proteins; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins
keywords: ATM; ATR; DDR; DNA damage response; DNA-PK; KSHV; Kaposi’s sarcoma-associated herpesvirus; lytic replication