VISUALIZATION OF THE TRANSVERSE CYTOSKELETAL NETWORK IN INSECT-FLIGHTMUSCLE BY SCANNING-ELECTRON MICROSCOPY

Located at the level of the Z-line, the transverse cytoskeletal networ k of insect-flight muscle interconnects adjacent myofibrils with one a nother, and interconnects peripheral myofibrils with the cell membrane . This network has been presumed to keep myofibrils in register, or to distribute tension laterally among myofibrils. In this study, we used scanning-electron microscopy to reveal details of the three-dimension al arrangement of this network. The network is seen to interconnect lo ngitudinal elements of the cytoskeletal network which surround each my ofibril. The arrangement is not unlike that seen in vertebrate skeleta l muscle. Interestingly, the transverse network makes contact with cel l components such as dense bodies and mitochondria. Such contacts impl y potential roles over and above those noted above. The network may be involved not only in mechanical function, but possibly also in intrac ellular communication. (C) 1995 Wiley-Liss, Inc.