| Range |
25,000-35,000 (60% of which are pol I) complexes/nucleus
|
| Organism |
Rat Rattus norvegicus |
| Reference |
Jackson DA, Pombo A, Iborra F. The balance sheet for transcription: an analysis of nuclear RNA metabolism in mammalian cells. FASEB J. 2000 Feb14(2):242-54. p.244 left column top paragraphPubMed ID10657981
|
| Primary Source |
[33] Coupar, B. E. H., Davies, J. A., and Chesterton, C. J. (1978) Quantification of hepatic transcribing RNA polymerase molecules, polyribonucleotide elongation rates and messenger RNA complexity in fed and fasted rats. Eur. J. Biochem. 84, 611–623PubMed ID639806
|
| Method |
"Various factors complicate the analysis of nascent
transcripts labeled in vivo (30, 32). However, in
principle, it should be a simple matter to establish
the number of nascent transcripts as cells have the
same number of active pols. Numbers of active pols can be determined in vitro using purified nuclei and
defined conditions with labeled precursors of known
specific activity and inhibitors to establish levels of
synthesis by the different pols. Following incorporation,
the amounts of radiolabel at internal and
terminal positions of the nascent chains allow the
number of active complexes to be established." |
| Comments |
"Using
this approach [see measurement method], rat liver nuclei were shown to have
25,000–35,000 engaged polymerase complexes,
60% of which were pol I (primary source). However, this type of
analysis is complicated by variable recoveries of active
pols in nuclei and the behavior of different
enzymes under the various conditions used (33–35)." |
| Entered by |
Uri M |
| ID |
111165 |