Document 0861
 DOCN  M9540861
 TI    Lack of LTR and ENV genetic variation during bovine leukemia
       virus-induced leukemogenesis.
 DT    9504
 AU    Willems L; Kerkhofs P; Burny A; Mammerickx M; Kettmann R; Faculte des
       Sciences agronomiques, Gembloux, Belgium.
 SO    Virology. 1995 Jan 10;206(1):769-72. Unique Identifier : AIDSLINE
       MED/95133228
 AB    Genetic variation of the Bovine Leukemia Virus (BLV) appears to be
       limited in vitro and during the latent phase of the disease. However,
       cells in tumors often harbor deleted proviruses that are defective for
       expression. In order to gain insight into the involvement of viral
       genetic variation during pathogenesis, the BLV LTR and the env proviral
       sequences were analyzed in tumor tissues. A sheep (M230) was injected
       with the cloned BLV provirus 344 and became persistently infected with
       circulating lymphocytes reaching 345,000/mm3. After 11 months, this
       infected sheep developed leukemia-lymphoma. DNA was extracted from
       peripheral blood leukocytes at the time of tumor development and the LTR
       and the env gene were amplified, using the polymerase chain reaction
       procedure, cloned, and sequenced. Twenty independent LTR and twenty env
       clones were analyzed. It appeared that the in vivo mutation rate in the
       env gene was 0.043% (eight mutations including seven transitions out of
       18,300 bp). Five point mutations (all transitions) were identified in
       the LTR, corresponding to 0.041% modifications (four mutations out of
       9740 bp). These mutation rate values (0.043 and 0.041) were close to
       those due to the Taq DNA polymerase errors (0.030%). Altogether, these
       data demonstrate the lack of genetic variation in the LTR and the env
       gene during this case of BLV-induced pathogenesis in vivo. They confirm
       that the defectiveness of some BLV proviruses in vivo, thus, is not a
       mandatory step in the leukemogenic process.
 DE    Animal  Base Sequence  Cattle  Enzootic Bovine Leukosis/*VIROLOGY
       *Genes, env  Genome, Viral  Leukemia Virus, Bovine/*GENETICS/PHYSIOLOGY
       Molecular Sequence Data  Point Mutation  *Repetitive Sequences, Nucleic
       Acid  Sheep  Support, Non-U.S. Gov't  *Variation (Genetics)  JOURNAL
       ARTICLE

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