Figure 3

miR-499 expression in medaka. Whole mount of a medaka embryo at 5 days post fertilization (dpf) (A) and a hatching larva at 10 dpf (B). miR-499 transcripts were detected in the notochord of the embryo and in cardiac and trunk skeletal muscles in the hatching larva. C) Ventral view of miR-499 expression in the heart of a 10-dpf larva. D) Transverse section of cardiac muscle at the position indicated in panel B. E) Transverse section from trunk skeletal muscle at the position indicated in panel B. Arrows indicate miR-499 expression in superficial slow muscle fibers. Transverse sections of adult cardiac (F) and trunk skeletal muscles (G). H) Higher magnification of the square indicated in panel G. miR-499 was expressed in cardiac but not in trunk muscle at the adult stage. I) miR-499 expression confirmed by next-generation sequencing. Vertical axis indicates miR-499 read numbers in each tissue. Scale bars: A-C, 500 μm; D-H, 200 μm.