Normal human placentas contain RNA-directed DNA polymerase activity like that in viruses

Jay Nelson, J. A. Leong, J. A. Levy

Research output: Contribution to journalArticle

49 Citations (Scopus)

Abstract

Extracts from over 100 normal human placentas have been examined for RNA-directed DNA polymerase (DNA nucleotidyltransferase, EC 2.7.7.7) activity. More than 80% of these placentas contained this enzyme activity, which banded at a density of 1.15-1.17 g/ml in sucrose. After heat treatment, this enzyme activity was shifted in density to 1.22-1.24 g/ml. The enzymatic activity was greater with (rC)n.(dG)12-18 than with (dC)n.(dG)12-18 and was not stimulated by (dG)12-18 alone. The product of the endogenous reaction, which was sensitive to RNase, had the characteristics of a small DNA associated with a large RNA by hydrogen bonding. Electron microscopic inspection of the material with a density of 1.15-1.17 g/ml revealed numerous retrovirus-like particles with central electron-dense cores and double-membraned envelopes. The enzyme may be associated with the retrovirus-like particles noted in the trophoblast layer of some human placentas.

Original languageEnglish (US)
Pages (from-to)6263-6267
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume75
Issue number12
StatePublished - 1978
Externally publishedYes

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RNA-Directed DNA Polymerase
Placenta
Retroviridae
Viruses
DNA Nucleotidyltransferases
Enzymes
Electrons
Trophoblasts
Hydrogen Bonding
Ribonucleases
Sucrose
Hot Temperature
RNA
DNA

ASJC Scopus subject areas

  • General
  • Genetics

Cite this

Normal human placentas contain RNA-directed DNA polymerase activity like that in viruses. / Nelson, Jay; Leong, J. A.; Levy, J. A.

In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 75, No. 12, 1978, p. 6263-6267.

Research output: Contribution to journalArticle

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