Abstract
Myofibrils, the contractile organelles of skeletal muscle, are highly ordered and precisely regulated actomyosin networks. Investigations of myofibril assembly are revealing the cellular mechanisms by which contractile components are arranged and regulated. In order to facilitate this research we have developed formal molecular genetics for myofibrillar proteins of Drosophila flight muscle. Presently, mutations can be used systematically to perturb or eliminate any of the classical myofibrillar proteins within these fibers, and the in vivo consequences can be conveniently evaluated using protein electrophoresis, electron microscopy, or by assaying flight performance. Here we review some recent progress.