Vorstufen der ribosomalen RNA in frei suspendierten Calluszellen der Petersilie (Petroselinum sativum) |
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Authors: | Gerhard Richter |
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Institution: | (1) Institut für Botanik der Technischen Universität, Herrenhäuser Straße 2, D-3000 Hannover, Germany |
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Abstract: | Summary Six high molecular weight, rapidly labelled RNA species were detected in freely suspended callus cells of Petroselinum sativum by means of isotope labelling and electrophoretic separation in agarose-polyacrylamide gels. On the basis of their migration in the latter the RNA species were calculated to have the following molecular weights: 2.9×106, 2,4×106, 1.9×106, 1.4×106, 1.0×106 and 0.75×106 daltons. Thus they can clearly be distinguished from the two ribosomal RNA species (1.3×106 and 0.7×106 daltons). During incubation of the cells with 3H]methyl-methionine as a methyl donator all six components incorporated radioactivity rapidly. With 3H]nucleosides or 3H]orotic acid as precursors the 2.9×106 and the 2.4×106 daltons RNA were labelled within 10 min, while the other high molecular weight species appeared after about 20 min of labelling.Prolongation to 45–120 min resulted in accumulation of radioactivity preferentially in the 1.4×106 and 0.75×106 daltons RNA and in the ribosomal RNA species. The results of cell fractionation experiments provide evidence that these rapidly labelled high molecular weight RNA species are synthesized in the cell nucleus. The kinetics of their synthesis together with the other data obtained strongly support the suggestion that these RNA species function as precursors in the processing of ribosomal RNA. The possible mechanism of this process is discussed. Verwendete Abkürzungen EDTA
Äthylendiamintetraessigsäure
- DNase
Desoxyribonuclease
- Imp./min
epm
- MAK
methyliertes Albumin an Kieselgur
- POPOP
1,4- bis (4-Methyl-5-Phenyloxazol)-Benzol
- PPO
2,5-Diphenyloxazol
- RNase
Ribonuclease
- S
Sedimentationskoeffizient in Svedberg-Einheiten
- SDS
Natriumdodecylsulfat
- TPE
Tris-Phosphat-EDTA-Puffer
- Tris
Tris-(hydroxymethyl)-aminomethan
- Upm
rpm |
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