Characterization of components of Z-bands in the fibrillar flight muscle of Drosophila melanogaster

• Published in: The Journal of cell biology 1989-11, Vol.109 (5), p.2157-2167
• Main Authors: Saide, J.D. (Boston University School of Medicine, Boston, MA), Chin-Bow, S, Hogan-Sheldon, J, Busquets-Turner, L, Vigoreaux, J.O, Valgeirsdottir, K, Pardue, M.L
• Format: Article
• Language: English
• Subjects: Actinin - analysis; Actinin - genetics; Animals; Antibodies; Antibodies, Monoclonal; Biological and medical sciences; Cell physiology; Cloning, Molecular; DNA - genetics; DROSOPHILA; Drosophila melanogaster; Electrophoresis, Polyacrylamide Gel; Flight muscles; Flight, Animal; Fluorescent Antibody Technique; Fundamental and applied biological sciences. Psychology; Gels; Honey bees; Immunoblotting; Insect proteins; Microscopy, Electron; Molecular and cellular biology; Monoclonal antibodies; MUSCLE; Muscle contraction; Muscle Proteins - analysis; MUSCLES; Muscles - analysis; Muscles - ultrastructure; MUSCULOS; Myofibrils; Myofibrils - analysis; Myofibrils - ultrastructure; PROTEINAS; PROTEINE; PROTEINS; Solar fibrils; Vertebrates
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.109.5.2157

Twelve monoclonal antibodies have been raised against proteins in preparations of Z-disks isolated from Drosophila melanogaster flight muscle. The monoclonal antibodies that recognized Z-band components were identified by immunofluorescence microscopy of flight muscle myofibrils. These antibodies have identified three Z-disk antigens on immunoblots of myofibrillar proteins. Monoclonal antibodies α:1-4 recognize a 90-100-kD protein which we identify as α-actinin on the basis of cross-reactivity with antibodies raised against honeybee and vertebrate α-actinins. Monoclonal antibodies P:1-4 bind to the high molecular mass protein, projectin, a component of connecting filaments that link the ends of thick filaments to the Z-band in insect asynchronous flight muscles. The anti-projectin antibodies also stain synchronous muscle, but, surprisingly, the epitopes here are within the A-bands, not between the A- and Z-bands, as in flight muscle. Monoclonal antibodies Z(210):1-4 recognize a 210-kD protein that has not been previously shown to be a Z-band structural component. A fourth antigen, resolved as a doublet (∼400/600 kD) on immunoblots of Drosophila fibrillar proteins, is detected by a cross reacting antibody, Z(400):2, raised against a protein in isolated honeybee Z-disks. On Lowicryl sections of asynchronous flight muscle, indirect immunogold staining has localized α-actinin and the 210-kD protein throughout the matrix of the Z-band, projectin between the Z- and A-bands, and the 400/600-kD components at the I-band/Z-band junction. Drosophila α-actinin, projectin, and the 400/600-kD components share some antigenic determinants with corresponding honeybee proteins, but no honeybee protein interacts with any of the Z(210) antibodies.