Fig. 2.

Muscle morphology in Mhc^K1728del mutant larvae and pupae. Larval body wall muscles and pupal IFM were labeled for myosin (Mhc) and Kettin/Titin (A and C) or Mhc and Obscurin (B and D). Each panel shows control animals (Top), Mhc^K1728del/+ animals (Middle), and Mhc^K1728del/Mhc^K1728del animals (Bottom). (A and B) Heterozygous Mhc^K1728del larvae show less-defined sarcomeric striations than control animals, Kettin/Titin is detected in slightly broad and jagged stripes at the Z-disks (arrow in A) and Obscurin as jagged stripes at M-bands (B). Homozygous larvae show disruptions in sarcomere and immature striations with myosin-containing A-bands appearing unstructured and extensively stretched (A). Z-disks (Kettin/Titin) and M-bands (Obscurin) appear reduced and discontinuous (A and B). (C and D) The IFMs of heterozygous pupae show less defined sarcomeric striated patterns. Homozygous Mhc^K1728del pupae display severely disrupted sarcomere structure and widely overextended myosin-containing A-bands. Staining with Obscurin revealed unstructured and immature M-band development (D). Depositions of myosin are detected in both heterozygous and homozygous Mhc^K1728del pupae, and were greater in number and size in homozygotes (C and D). (Scale bars, 5 µm.)