title: Isolation of replication-competent molecular clones of visna virus.
abstract: Visna virus is the prototypic member of a subfamily of retroviruses responsible for slow infections of animals and humans. As a part of our investigation of the functions of viral gene products in virus replication, we have isolated three infectious molecular clones and determined the complete nucleotide sequences of two of the clones. We have also characterized the progeny of the biologically cloned viral stocks and of the infectious clones and document considerable heterogeneity in plaque size and antigenic phenotype of the former that is reduced to near homogeneity in the progeny of the infectious clones. It thus should now be possible to trace the emergence of antigenic variants of visna virus as well as ascribe defined functions to structural and regulatory genes of the virus in determining neurovirulence and the slow tempo of infection.
authors.affiliation: Department of Microbiology, University of Minnesota, Minneapolis 55455.
authors.forename: K A
authors.initials: KA
authors.lastname: Staskus
authors.forename: E F
authors.initials: EF
authors.lastname: Retzel
authors.forename: E D
authors.initials: ED
authors.lastname: Lewis
authors.forename: J L
authors.initials: JL
authors.lastname: Silsby
authors.forename: S
authors.initials: S
authors.lastname: St Cyr
authors.forename: J M
authors.initials: JM
authors.lastname: Rank
authors.forename: S W
authors.initials: SW
authors.lastname: Wietgrefe
authors.forename: A T
authors.initials: AT
authors.lastname: Haase
authors.forename: R
authors.initials: R
authors.lastname: Cook
authors.forename: D
authors.initials: D
authors.lastname: Fast
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D002831:Choroid Plexus; D002872:Chromosome Deletion; D003001:Cloning, Molecular; D004251:DNA Transposable Elements; D004279:DNA, Viral / Q000235:genetics / Q000302:isolation & purification; D005814:Genes, Viral; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D012756:Sheep; D010948:Viral Plaque Assay; D014779:Virus Replication; D014790:Visna-maedi virus / Q000235:genetics / Q000502:physiology*
chemical_list: D004251:DNA Transposable Elements; D004279:DNA, Viral