       Document 0522
 DOCN  M9630522
 TI    Genetic rearrangements occurring during a single cycle of murine
       leukemia virus vector replication: characterization and implications.
 DT    9603
 AU    Parthasarathi S; Varela-Echavarria A; Ron Y; Preston BD; Dougherty JP;
       Department of Molecular Genetics and Microbiology, Robert Wood; Johnson
       Medical School, University of Medicine and Dentistry of; New Jersey,
       Piscataway 08854-5635, USA.
 SO    J Virol. 1995 Dec;69(12):7991-8000. Unique Identifier : AIDSLINE
       GENBANK/J02257
 AB    Retroviruses evolve at rapid rates, which is presumably advantageous for
       responding to selective pressures. Understanding the basic mutational
       processes involved during retroviral replication is important for
       comprehending the ability of retroviruses to escape immunosurveillance
       and antiviral drug treatment. Moreover, since retroviral vectors are
       important vehicles for somatic cell gene therapy, knowledge of the
       mechanism of retroviral variation is critical for anticipating untoward
       mutational events occurring during retrovirus-medicated gene transfer.
       The focus of this report is to examine the spectrum of genomic
       rearrangements arising during a single cycle of Moloney murine leukemia
       virus (MoMLV) vector virus replication. An MoMLV vector containing the
       herpes simplex virus thymidine kinase (tk) gene was constructed. MoMLV
       vector virus was produced in packaging lines, and target cells were
       infected. From a total of 224 mutant proviruses analyzed, 114 had gross
       rearrangements readily detectable by Southern blotting. The remaining
       proviruses were of parental size. PCR and DNA sequence analysis of 73 of
       the grossly rearranged mutant proviruses indicated they resulted from
       deletions, combined with insertions, duplications, and complex mutations
       that were a result of multiple genomic alterations in the same provirus.
       Complex hypermutations distinct from those previously described for
       spleen necrosis virus and human immunodeficiency virus were detected.
       There was a correlation between the mutation breakpoints and
       single-stranded regions in the predicted viral RNA secondary structure.
       The results also confirmed that the tk gene is inactivated at an average
       rate of about 8.8% per cycle of retroviral replication, which
       corresponds to a rate of mutation of 3%/kbp.
 DE    Animal  Base Sequence  Cloning, Molecular  DNA Primers  DNA,
       Viral/ANALYSIS  *Gene Rearrangement  *Genes, Viral  Genetic Vectors
       Human  HIV/GENETICS  L Cells  Mice  Models, Structural  Molecular
       Sequence Data  Moloney Leukemia Virus/*GENETICS/*PHYSIOLOGY  Mutagenesis
       Nucleic Acid Conformation  Polymerase Chain Reaction  RNA,
       Viral/CHEMISTRY/GENETICS  Sequence Deletion
       Simplexvirus/ENZYMOLOGY/GENETICS  Species Specificity  Support, Non-U.S.
       Gov't  Support, U.S. Gov't, P.H.S.  Thymidine
       Kinase/BIOSYNTHESIS/GENETICS  *Virus Replication  3T3 Cells  JOURNAL
       ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).

