DNA polymerases in human lymphoblastoid cells infected with simian sarcoma virus

Lewis, Brian J.; Abrell, John W.; Smith, R G; Gallo, Robert C.

doi:10.1016/0005-2787(74)90076-8

Cited by 67 publications

(13 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…DNA polymerase from Rauscher murine leukemia virus was purified by chromatography on Sephadex and phosphocellulose (15). The large DNA polymerase from phytohemagglutinin-stimulated human lymphocytes (16) was purified as outlined by Lewis et al (17). DNA polymerase of sea urchin nuclei (18) and E. coli DNA polymerase I (2, 19) were purified as described.…”

Section: Methodsmentioning

confidence: 99%

Reverse Transcriptase: Correlation of Zinc Content with Activity

Poiesz

Seal

Loeb

1974

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Evidence is presented that DNA polymerase of avian myeloblastosis virus has an obligatory zinc requirement for activity. Previous studies indicate that the purified polymerase contains zinc in a stoichiometry of about 1 g-atom/mole. We now find that the enzyme-bound zinc is exchangeable with radioactive 65Zn; after isoelectric focusing, the radioactive 65Zn is coincident with polymerase activity. Dialysis of the 65Zn-labeled polymerase against the chelator, 1,10-phenanthroline, results in a progressive loss of radioactive 65Zn and polymerase activity. Thereupon, incubation of the inactivated enzyme with Zn2+ fully restores activity. Thus, the DNA polymerase present in an oncogenic RNA virus, like animal DNA polymerases, can be rigorously classified as a zinc metalloenzyme. DNA polymerase of avian myeloblastosis virus is inactivated by 1,10-phenanthroline at a much faster rate than the bacterial and animal DNA polymerases that have been tested. It may, therefore, be possible to inactivate selectively DNA polymerases from animal tumor viruses by brief exposure to appropriate metal chelators.Recent metal analysis and inhibition by chelating agents suggest that DNA polymerases are zinc metalloenzymes. Homogeneous DNA polymerase I of Escherichia coli has been shown to contain 1.0 + 0.15 g-atom of zinc per mole of enzyme (1, 2). Removal of zinc is accompanied by a proportional loss of activity; addition of zinc to the apoenzyme results in full restoration of activity (2). DNA polymerases from sea urchin nuclei (1) and T4 bacteriophage (2) have also been shown to contain zinc in stoichiometric amounts. In addition, partially purified DNA polymerases from phylogenetically divergent sources are inhibited by metal chelators (1-5). These correlated findings suggest that DNA polymerases generically are zinc metalloenzymes.Since the DNA polymerases present in RNA tumor viruses can copy RNA templates, it was initially thought that the mechanism for catalysis of viral polymerases was different from that of cellular polymerases. For this reason they were termed "reverse transcriptases." However, the ability to copy RNA does not appear to be a unique property of viral enzymes; recently E. coli DNA polymerase I has been shown to copy faithfully a variety of natural RNA templates (6-8). Also, metal and substrate requirements for catalysis by viral and cellular polymerases appear to be similar, if not identical. It is therefore crucial to determine if viral polymerases are also zinc metalloenzymes. Zinc has been found in the purified "reverse transcriptase" from avian myeloblastosis virus by us, using atomic absorption spectroscopy (9), and independently by Auld et al., using microwave induced emission spectrometry (10, 11). However, in order to establish this enzyme as a zinc metalloenzyme, it is necessary to show an obligatory requirement of zinc for enzymatic activity (12). We now report evidence for such a requirement. The removal of zinc from avian myeloblastosis DNA polymerase results in loss of activity. The readditi...

show abstract

Section: Methodsmentioning

confidence: 99%

Reverse Transcriptase: Correlation of Zinc Content with Activity

Poiesz

Seal

Loeb

1974

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…In addition, the supernatant activity differs from the pellet in being stimulated by RNase (Table I), and in being unable to copy poly-(C).oligo(dG) ( Table II Loeb, 1975;Bollum, 1975). Although dissimilar from the major cytoplasmic and nuclear enzymes (DNA polymerase x and f8) which have a preference for DNA templates, the leukaemic pellet enzyme resembles the DNA polymerase y or III (the reverse transcriptase-like cellular enzyme (Lewis et al, 1974)) in displaying a preference for poly(A).oligo-(dT). The leukaemic pellet enzyme however, unlike DNA polymerase y, can copy poly(C) .…”

Section: Activity Of Normal and Leukaemic Plasma Pelletsmentioning

confidence: 93%

DNA polymerase activity in plasma from leukaemic guinea-pigs

Hallinan¹,

Maclean²

1976

Br J Cancer

View full text Add to dashboard Cite

Summary.-Measurement of DNA polymerase in leukaemic guinea-pig plasma reveals the presence of low levels of sedimentable and non-sedimentable enzymic activities. Since the sedimentable DNA polymerase is ribonuclease sensitive, uses poly(C).oligo(dG) as template, and bands in a sucrose density gradient at 117 g/ml it is thought to be the GPLV-associated reverse transcriptase. The soluble DNA polymerase is stimulated by ribonuclease and is probably of cellular origin.

show abstract

“…Two cytoplasmic y-polymerases, I and II have been found in HeLa and one of these (II) appears to be similar to the nuclear ypolymerase [85] , y-polymerase 1 copies only poly (A) among homoribopolymers, but II is able to copy poly (C), poly (U) or poly (I) in addition. Both sediment at 6.1-6.3 S [86] giving an apparent mol. wt of 110 000.…”

Section: Dna Polymeruse-ymentioning

confidence: 99%

“…(dT)= neither will use poly (C). (dC)n or natural RNA to any appreciable extent unlike reverse transcriptase [85,86].…”

Section: Dna Polymeruse-ymentioning

confidence: 99%