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Nucleolar necklaces in chick embryo fibroblast cells. II. Microscope observations of the effect of adenosine analogues on nucleolar necklace formation

The round nucleoli of chick embryo fibroblast cells, when exposed to adenosine (2 mM)or to a number of adenosine analogues, lose material and unravel over a period of several hours to become beaded strands, 20 mu M in length, termed nucleolar necklaces (NN). Light microscope observations on this pro...

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Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 1975
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2109423/
https://www.ncbi.nlm.nih.gov/pubmed/1092701
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description The round nucleoli of chick embryo fibroblast cells, when exposed to adenosine (2 mM)or to a number of adenosine analogues, lose material and unravel over a period of several hours to become beaded strands, 20 mu M in length, termed nucleolar necklaces (NN). Light microscope observations on this process are described. Biochemical experiments have revealed that most of these analogues interfere with both messenger RNA synthesis and ribosome synthesis, causing extensive degradation of the preribosome species containing 32S RNA although most of the preribosomes containing 18S RNA survive. We suggest that it is the depletion from the nucleolus of the adhesive 32S and 28S RNA preribosomes which allows the remaining nucleolar apparatus to spread apart into the NN configuration. Also required for the maintenance of the NN structure is the synthesis of some ribosomal RNA (rRNA) possibly present as rRNA "feathers" on the DNA. The addition of inhibitors of rRNA synthesis such as actinomycin D to the NN-containing cells causes loss of rRNA. Then a contraction and collapse of the NN structure into small dense spheres is observed.
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spelling pubmed-21094232008-05-01 Nucleolar necklaces in chick embryo fibroblast cells. II. Microscope observations of the effect of adenosine analogues on nucleolar necklace formation J Cell Biol Articles The round nucleoli of chick embryo fibroblast cells, when exposed to adenosine (2 mM)or to a number of adenosine analogues, lose material and unravel over a period of several hours to become beaded strands, 20 mu M in length, termed nucleolar necklaces (NN). Light microscope observations on this process are described. Biochemical experiments have revealed that most of these analogues interfere with both messenger RNA synthesis and ribosome synthesis, causing extensive degradation of the preribosome species containing 32S RNA although most of the preribosomes containing 18S RNA survive. We suggest that it is the depletion from the nucleolus of the adhesive 32S and 28S RNA preribosomes which allows the remaining nucleolar apparatus to spread apart into the NN configuration. Also required for the maintenance of the NN structure is the synthesis of some ribosomal RNA (rRNA) possibly present as rRNA "feathers" on the DNA. The addition of inhibitors of rRNA synthesis such as actinomycin D to the NN-containing cells causes loss of rRNA. Then a contraction and collapse of the NN structure into small dense spheres is observed. The Rockefeller University Press 1975-05-01 /pmc/articles/PMC2109423/ /pubmed/1092701 Text en This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/).
spellingShingle Articles
Nucleolar necklaces in chick embryo fibroblast cells. II. Microscope observations of the effect of adenosine analogues on nucleolar necklace formation
title Nucleolar necklaces in chick embryo fibroblast cells. II. Microscope observations of the effect of adenosine analogues on nucleolar necklace formation
title_full Nucleolar necklaces in chick embryo fibroblast cells. II. Microscope observations of the effect of adenosine analogues on nucleolar necklace formation
title_fullStr Nucleolar necklaces in chick embryo fibroblast cells. II. Microscope observations of the effect of adenosine analogues on nucleolar necklace formation
title_full_unstemmed Nucleolar necklaces in chick embryo fibroblast cells. II. Microscope observations of the effect of adenosine analogues on nucleolar necklace formation
title_short Nucleolar necklaces in chick embryo fibroblast cells. II. Microscope observations of the effect of adenosine analogues on nucleolar necklace formation
title_sort nucleolar necklaces in chick embryo fibroblast cells. ii. microscope observations of the effect of adenosine analogues on nucleolar necklace formation
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2109423/
https://www.ncbi.nlm.nih.gov/pubmed/1092701