Identification of cis sequences required for lytic DNA replication and packaging of murine gammaherpesvirus 68.
Human gammaherpesviruses are associated with lymphomas and other malignancies. Murine gammaherpesvirus 68 (MHV-68) infection of mice has emerged as a model for understanding gammaherpesvirus pathogenesis in vivo. In contrast to human gammaherpesviruses, MHV-68 replicates in permissive cell lines in a robust manner, presenting an efficient model to study the basic mechanisms for DNA replication and recombination processes. In addition, MHV-68 also infects a broad range of cells of different tissue types and from different host species, and the viral genome persists as an episome in infected cells. These features make MHV-68 an attractive system on which to build gene delivery vectors. We have therefore undertaken a study to identify the cis elements required for MHV-68 genome replication and packaging. Here we report that an 8.4-kb MHV-68 genomic fragment between ORF66 and ORF73 conferred on the plasmid the ability to replicate; replication required the presence of either de novo viral infection or viral reactivation from latency. We further mapped the origin of lytic replication (oriLyt) to a 1.25-kb region. Moreover, we demonstrated that the terminal repeat of the viral genome is sufficient for packaging of the replicated oriLyt plasmid into mature viral particles. Functional identification of the MHV-68 oriLyt and packaging signal has laid a foundation for investigating the mechanisms controlling gammaherpesvirus DNA replication during the viral lytic phase and will also serve as a base on which to design gene delivery vectors.
Deng
Hongyu
H
Department of Molecular & Medical Pharmacology, Dental Research Intsitute, UCLA AIDS Institute, Jonsson Comprehensive Cancer Center, University of California at Los Angeles, Los Angeles 90095-1735, USA. hdeng@mednet.ucla.edu
Chu
Julia T
JT
Park
No-Hee
NH
Sun
Ren
R
D000818:Animals; D002460:Cell Line; D006224:Cricetinae; D004261:DNA Replication / Q000235:genetics*; D004279:DNA, Viral / Q000235:genetics* / Q000502:physiology; D005822:Genetic Vectors / Q000235:genetics; D019288:Herpesvirus 8, Human / Q000235:genetics / Q000502:physiology; D051379:Mice; D016366:Open Reading Frames / Q000235:genetics; D018741:Replication Origin / Q000235:genetics / Q000502:physiology; D018144:Rhadinovirus / Q000235:genetics* / Q000502:physiology*; D020079:Terminal Repeat Sequences / Q000235:genetics / Q000502:physiology; D014775:Virus Activation / Q000235:genetics*; D019065:Virus Assembly / Q000235:genetics*
D004279:DNA, Viral