title: Open reading frame L1 of Marek's disease herpesvirus is not essential for in vitro and in vivo virus replication and establishment of latency.
abstract: Two mutant CV1988 Marek's disease virus (MDV) strains were developed in which a part of ORF L1 was replaced by lacZ with the SV40 early promoter. These mutant strains, CVIL1LacZ-A and -B, were inoculated into chickens to test the hypothesis that ORF L1 is involved in the induction and/or maintenance of latency. Mutant virus could be reisolated from lymphocytes obtained from chickens during both the lytic and latent phase of infection, indicating that ORF L1 is not essential for the induction and/or maintenance of latency or the reactivation from latency. Beta-galactosidase-positive lymphocytes were detected during the latent infection demonstrating that the SV40 early promoter can be active in recombinant MDV strains during latent infection. Although the insertion of lacZ was stable in cell culture, recombination within lacZ and the BamHI-L fragment was observed during in vivo infection.
authors.affiliation: Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA. kas24@Cornell.edu
authors.forename: K A
authors.initials: KA
authors.lastname: Schat
authors.forename: B J
authors.initials: BJ
authors.lastname: Hooft van Iddekinge
authors.forename: H
authors.initials: H
authors.lastname: Boerrigter
authors.forename: P H
authors.initials: PH
authors.lastname: O'Connell
authors.forename: G
authors.initials: G
authors.lastname: Koch
mesh_terms: D000818:Animals; D000956:Antigens, Viral / Q000235:genetics; D001483:Base Sequence; D002478:Cells, Cultured; D002642:Chick Embryo; D002645:Chickens; D017931:DNA Primers / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics / Q000302:isolation & purification; D015870:Gene Expression; D008381:Herpesvirus 2, Gallid / Q000235:genetics* / Q000472:pathogenicity / Q000502:physiology*; D007763:Lac Operon; D008380:Marek Disease / Q000209:etiology / Q000821:virology; D016254:Mutagenesis, Insertional; D016366:Open Reading Frames; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D017384:Sequence Deletion; D013539:Simian virus 40 / Q000235:genetics; D014774:Virulence / Q000235:genetics; D014779:Virus Replication / Q000235:genetics*
chemical_list: D000956:Antigens, Viral; D017931:DNA Primers; D004279:DNA, Viral