Studies on Cardiac Myofibrillogenesis with Antibodies to Titin, Actin, Tropomyosin, and Myosin

• Published in: The Journal of cell biology Vol. 107; no. 3; pp. 1075 - 1083
• Main Authors: Wang, Seu-Mei, Greaser, Marion L., Schultz, Edward, Bulinski, Jeannette C., Jim J.-C. Lin, Lessard, James L.
• Format: Journal Article
• Language: English
• Published: New York, NY Rockefeller University Press 01.09.1988; The Rockefeller University Press
• Subjects: Actins; Actins - analysis; Actins - immunology; Animals; Antibodies; Antibodies - immunology; Antibodies, Monoclonal - immunology; Biological and medical sciences; Cell culture techniques; Cell membranes; Cell structures and functions; Cells; Cells, Cultured; Chick Embryo; Connectin; Fluorescent Antibody Technique; Fundamental and applied biological sciences. Psychology; Gels; Immunoassay; Miscellaneous; Molecular and cellular biology; Muscle development; Muscle Proteins - analysis; Muscle Proteins - immunology; Myocardium; Myocardium - analysis; Myocardium - ultrastructure; Myofibrils; Myofibrils - analysis; Myofibrils - physiology; Myosins - analysis; Myosins - immunology; Protein Kinases; Sarcomeres; Space life sciences; Tropomyosin - analysis; Tropomyosin - immunology; Cell culture; Myofibril; Rat; Tropomyosin; Rodentia; Stress fiber-like structure; Actins; Monoclonal antibody; Myocyte; Vertebrata; Mammalia; Ultrastructure; Myosin; Immunofluorescence; Sarcomere
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.107.3.1075

Cardiac myofibrillogenesis was examined in cultured chick cardiac cells by immunofluorescence using antibodies against titin, actin, tropomyosin, and myosin. Primitive cardiomyocytes initially contained stress fiber-like structures (SFLS) that stained positively for α actin and/or muscle tropomyosin. In some cases the staining for muscle tropomyosin and α actin was disproportionate; this suggests that the synthesis and/or assembly of these two isoforms into the SFLS may not be stoichiometric. The α actin containing SFLS in these myocytes could be classified as either central or peripheral; central SFLS showed developing sarcomeric titin while peripheral SFLS had weak titin fluorescence and a more uniform stain distribution. Sarcomeric patterns of titin and myosin were present at multiple sites on these structures. A pair of titin staining bands was clearly associated with each developing A band even at the two or three sarcomere stage, although occasional examples of a titin band being associated with a half sarcomere were noted. The appearance of sarcomeric titin patterns coincided or preceded sarcomere periodicity of either α actin or muscle tropomyosin. The early appearance of titin in myofibrillogenesis suggests it may have a role in filament alignment during sarcomere assembly.