Mutant Muscle Sarcomere, Drosophila larva

Contractile muscle filaments of a Drosophila larva showing actin filaments (red) and myosin filaments (green). The Drosophila is carrying a loss-of-function mutation in the Mical protein, causing dramatic defects in the regular arrangement of sarcomeric filaments. A regular sarcomeric pattern is required to generate enormous forces during muscle contraction. Dissected Drosophila third instar larva. Image width is 177 micrometers. See image B0009384 for a normal muscle sarcomere.