Fig. 6. Mef2 controls a transcriptional module involved in thick filament
assembly. Confocal immunofluorescence of sarcomeric components in a 24-hpf
midbody somite of control or mef2d/c MO-injected zebrafish embryos in
fast (A, medial) or slow (A, superficial, B-F) fibres; lateral view slice and
insets of stack, anterior to left, dorsal to top. (A) MyHC is absent
from fast fibres (asterisk) and concentrated at fibre ends in slow fibres
(arrowhead) in morphants, whereas actin is diffusely dispersed in cytoplasm of
both fibre types (arrows). Blue dashes indicate somite borders. (B-D)
z-line components
-actinin and titin and thin filament protein
-tropomyosin are concentrated in cytoplasmic puncta (arrowheads) and at
fibre termini (arrows) after Mef2 knockdown. (E,F) M-line
component MyBP-C is absent from residual myofibrils in morphants with regular
sarcomere z-line spacing (arrowheads). Scale bars: 20 µm.