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 language | English (US) |
|---|---|
| Pages (from-to) | 6263-6267 |
| Number of pages | 5 |
| Journal | Proceedings of the National Academy of Sciences of the United States of America |
| Volume | 75 |
| Issue number | 12 |
| State | Published - 1978 |
| Externally published | Yes |
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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 journal › Article
}
TY - JOUR
T1 - Normal human placentas contain RNA-directed DNA polymerase activity like that in viruses
AU - Nelson, Jay
AU - Leong, J. A.
AU - Levy, J. A.
PY - 1978
Y1 - 1978
N2 - 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.
AB - 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.
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M3 - Article
C2 - 83652
AN - SCOPUS:0018237312
VL - 75
SP - 6263
EP - 6267
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
SN - 0027-8424
IS - 12
ER -