Abstract |
The incorporation of [14C]orotate and [14C] uridine into UMP residues of hnRNA ( heterogeneous nuclear RNA) and pre-rRNA (precursors to rRNA) of Eharlich ascites-tumour cells was compared: orotate was incorporated at a markedly higher rate into hnRNA. On the other hand, the rate of incorporation of uridine into pre-rRTNA was even somewhat higher than into hnRNA. The ratio of specific radioactivities of CMP to UMP residues in pre-rRNA and hnRNA was studied. At all times of labelling this ratio was similar for both RNA species independently of the precursor used. On addition of excess unlabelled uridine, the CMP/ UMP labelling ratio in both pre-rRNA and hnRNA rose. However, this increase was much more pronounced with hnRNA. It is concluded that nuclear pyrimidine nucleotide pool for RNA synthesis is compartmentalized. The synthesis of hnRNa is supplied preferentially by the large and the small compartment, respectively. A detailed model for the cellular compartmentation of uridine nucleotide precursors to RNA is proposed.U
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Authors | D D Genchev, M B Kermekchiev, A A Hadjiolov |
Journal | The Biochemical journal
(Biochem J)
Vol. 188
Issue 1
Pg. 85-90
(Apr 15 1980)
ISSN: 0264-6021 [Print] England |
PMID | 7406891
(Publication Type: Journal Article)
|
Chemical References |
- Carbon Radioisotopes
- Pyrimidine Nucleotides
- RNA, Heterogeneous Nuclear
- RNA, Ribosomal
- Orotic Acid
- Uridine
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Topics |
- Animals
- Base Composition
- Carbon Radioisotopes
- Carcinoma, Ehrlich Tumor
(metabolism)
- Cell Compartmentation
- Cell Line
- Kinetics
- Mice
- Models, Biological
- Orotic Acid
(metabolism)
- Pyrimidine Nucleotides
(metabolism)
- RNA, Heterogeneous Nuclear
(biosynthesis)
- RNA, Ribosomal
(biosynthesis)
- Uridine
(metabolism)
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