Observations have been made of ultrastructural modifications induced in the nuclei of differentiating amphibian embryonic cells cultured in the presence of Actinomycin D. Of particular interest are regions within the nucleus (regions otherwise rather empty) containing loose groupings of uniform threads having a diameter of around 200 A. These threads have been observed in continuous lengths up to 0.5 µ, and appear to be composed of subfilaments. It is suggested, after taking account of some recent work on lampbrush chromosomes, that these threads are lengths of uncoiled chromosome in a condition of heterosynthetic inhibition. It is further suggested that active and inactive portions of the genome may be distinguishable by the facility with which they can be induced to undergo this ultrastructural modification.
Article|
May 01 1964
THE EFFECTS OF ACTINOMYCIN D ON THE ULTRASTRUCTURE OF THE NUCLEUS OF THE AMPHIBIAN EMBRYONIC CELL
K. W. Jones,
K. W. Jones
From the Institute of Animal Genetics, Edinburgh, Scotland
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T. R. Elsdale
T. R. Elsdale
From the Institute of Animal Genetics, Edinburgh, Scotland
Search for other works by this author on:
K. W. Jones
From the Institute of Animal Genetics, Edinburgh, Scotland
T. R. Elsdale
From the Institute of Animal Genetics, Edinburgh, Scotland
Received:
July 09 1963
Online Issn: 1540-8140
Print Issn: 0021-9525
Copyright © 1964 by The Rockefeller Institute Press
1964
J Cell Biol (1964) 21 (2): 245–252.
Article history
Received:
July 09 1963
Citation
K. W. Jones, T. R. Elsdale; THE EFFECTS OF ACTINOMYCIN D ON THE ULTRASTRUCTURE OF THE NUCLEUS OF THE AMPHIBIAN EMBRYONIC CELL . J Cell Biol 1 May 1964; 21 (2): 245–252. doi: https://doi.org/10.1083/jcb.21.2.245
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