A new class of filaments intermediate in diameter between actin and myosin filaments has been demonstrated in skeletal muscle cells cultured from chick embryos. These filaments, which account for the majority of free filaments, average 100 A in diameter. They may run for more than 2 µ in a single section and can be distinguished in size and appearance from the thick and thin filaments assembled into myofibrils. The 100-A filaments are seen scattered throughout the sarcoplasm at all stages of development and show no obvious association with the myofibrils. The 100-A filaments are particularly conspicuous in myotubes fragmented by the mitotic inhibitors, colchicine and Colcemid. In addition, filaments similar in size and appearance to those found in myotubes are present in fibroblasts, chondrocytes, and proliferating mononucleated myoblasts. The 100-A filaments are present in cells arrested in metaphase by mitotic inhibitors. Definitive thick (about 150 A) or thin (about 60 A) myofilaments are not found in skeletal myogenic cells arrested in metaphase. Myogenic cells arrested in metaphase do not bind fluorescein-labeled antibody directed against myosin or actin. For these reasons, it is concluded that not all "thin" filaments in myogenic cells are uniquely associated with myogenesis.
Article|
September 01 1968
MITOSIS AND INTERMEDIATE-SIZED FILAMENTS IN DEVELOPING SKELETAL MUSCLE
In Special Collection:
JCB65: Cytoskeleton
H. Ishikawa,
H. Ishikawa
From the Departments of Biochemistry and Anatomy, the School of Medicine, the University of Pennsylvania, Philadelphia, Pennsylvania 19104
Search for other works by this author on:
R. Bischoff,
R. Bischoff
From the Departments of Biochemistry and Anatomy, the School of Medicine, the University of Pennsylvania, Philadelphia, Pennsylvania 19104
Search for other works by this author on:
H. Holtzer
H. Holtzer
From the Departments of Biochemistry and Anatomy, the School of Medicine, the University of Pennsylvania, Philadelphia, Pennsylvania 19104
Search for other works by this author on:
H. Ishikawa
From the Departments of Biochemistry and Anatomy, the School of Medicine, the University of Pennsylvania, Philadelphia, Pennsylvania 19104
R. Bischoff
From the Departments of Biochemistry and Anatomy, the School of Medicine, the University of Pennsylvania, Philadelphia, Pennsylvania 19104
H. Holtzer
From the Departments of Biochemistry and Anatomy, the School of Medicine, the University of Pennsylvania, Philadelphia, Pennsylvania 19104
Received:
April 11 1968
Online Issn: 1540-8140
Print Issn: 0021-9525
Copyright © 1968 by The Rockefeller University Press.
1968
J Cell Biol (1968) 38 (3): 538–555.
Article history
Received:
April 11 1968
Citation
H. Ishikawa, R. Bischoff, H. Holtzer; MITOSIS AND INTERMEDIATE-SIZED FILAMENTS IN DEVELOPING SKELETAL MUSCLE . J Cell Biol 1 September 1968; 38 (3): 538–555. doi: https://doi.org/10.1083/jcb.38.3.538
Download citation file: