@entity1778 virus (HaLV) contains a DNA polymerase different from those of @entity19 and avian viruses. No endogenous reaction directed by the 60 to 70S RNA of HaLV could be demonstrated in detergenttreated HaLV virions, nor could the purified DNA polymerase copy added viral RNA. The virion RNA could, however, act as template for added avian myeloblastosis virus DNA polymerase and the HaLV DNA polymerase could efficiently utilize homopolymers as templates. The HaLV enzyme was like other reverse transcriptases in that certain ribohomopolymers were much better templates than the homologous deoxyribohomopolymers. No ribonuclease H activity could be shown in the HaLV enzyme, but neither could activity be found in the @entity19 @entity1778 virus DNA polymerase. The hamster enzyme was unique in that poly(A) .oligo(dT) was a poor template, and globin mRNA primed with oligo(dT) was totally inactive as a template. Its uniqueness was also indicated by its subunit composition; electrophoresis of the HaLV DNA polymerase in @entity3208 -containing @entity2975 gels revealed equimolar amounts of two polypeptides of molecular weight 68,000 and 53,000. The sedimentation rate of the enzyme in @entity653 gradients was consistent with a structure containing one each of the two polypeptides. The enzyme thus appears to be structurally distinct from other known virion DNA polymerases. Its inability to carry out an endogenous reaction in vitro might result from an inability to utilize certain primers.

XXXX virus: lack of endogenous DNA synthesis and unique structure of its DNA polymerase.

@entity3208 :: ('MESH:D012967', 'Chemical') :: ['sodium dodecyl sulfate'] @entity19 :: ('10090', 'Species') :: ['murine'] @entity653 :: ('MESH:D005990', 'Chemical') :: ['glycerol'] @entity1778 :: ('MESH:D007938', 'Disease') :: ['Infectious hamster leukemia', 'leukemia'] @entity2975 :: ('CHEBI:51135', 'Chemical') :: ['polyacrylamide']
@entity1778 :: (MESH:D007938,Disease) :: ['Hamster leukemia']
