Fig. 2
Fig. 2
Skeletal muscle hypotrophy and precocious differentiation in Ddx27 deficiency.
(A-B) Histology of longitudinal skeletal muscle sections in control and ddx27 mutant stained with toluidine blue exhibiting enlarged nucleoli (arrowhead) and areas lacking sarcomeres (arrow) at 5 dpf. High magnification view (boxed area) (C-G) Transmission electron micrographs of skeletal muscles (longitudinal view: C-E, and cross-section view: F-G) in control and ddx27 mutant (5 dpf). Arrows indicating disorganized sarcomere (H) Quantification of myofiber size in control and ddx27 mutant fish (5 dpf) (n = 10) (I) qRT-PCR of control and ddx27 mutant fish showed a reduction in the expression of muscle stem cell markers (pax3, pax7) and an increase in expression of myogenic commitment genes (myod1 and myf5). The expression of late differentiation markers was reduced in ddx27 fish suggesting that pre-mature expression of early myogenic genes results in abnormal disorganization of skeletal muscles.