| Autor: |
Santelli RV, Machado-Santelli GM, Lara FJ |
| Jazyk: |
angličtina |
| Zdroj: |
Chromosoma [Chromosoma] 1976 Jun 30; Vol. 56 (1), pp. 69-84. |
| DOI: |
10.1007/BF00293731 |
| Abstrakt: |
A method for the isolation of polytene nuclei from salivary glands cells of the Diptera Rhynchosciara americana is described. The stage-specific morphological pattern of the chromosome is maintained during the isolation. The isolated nuclei show two distinct RNA polymerase activities, namely I and II, characterized on the basis of ionic requirements and alpha-amanitin sensitivity. Studies of the product under the incubation conditions show that the system allows the synthesis of high-molecular weight RNA, beside a low molecular weight peak which may comprise pre-4S and 5S RNAs. Autoradiographic studies carried out in the presence or absence of the toxin alpha-amanitin showed that micronucleoli contain products of RNA polymerase type I activity (ribosomal RNA) and that the DNA puffs are engaged in alpha-amanitin sensitive RNA synthesis and thus are sites of polymerase type II activity. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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