Figure 1.
Whole-Mount and Histological Analyses of Skeletal Muscle Regeneration Directed by Varying Gene Dosages of MyoD and Myf5 in Satellite Cells
(A–D) Whole-mount images of uninjured and injured (11 dpi) TA muscles from MyoD-SA (A and B) and dKO (C and D) mice. Mice carried the Cre-dependent GFP reporter, R26NG. Fluorescence images in (A) and (C) are shown in (B) and (D), respectively. GFP+ satellite cells in uninjured muscles are not visible at this magnification and exposure (B and D); top. The exposure times to capture the GFP images were 126 ms (B) and 892 ms (D). Scale bars represent 1 mm (A–D).
(E–L) Histological analyses at 11 dpi (E–H) and 31 dpi (I–L). Sections were stained with H&E (E–K) or oil red O (L). The same section is shown in (K and L). dKO muscle was filled with adipocytes (black asterisks) (K and L) and apparent fibrotic tissue (white asterisks) (K). Scale bars represent 50 μm.
(M–O) Lineage-labeled dKO cells populated the injured TA muscle. The boxed area in (M) is magnified in (N). Occasional, minute fibers are evident in (O) (arrows).
(P) Myf5-SA mice exhibited the typical architecture of regenerated muscle at 31 dpi.
(Q–T) PCNA immunofluorescence of Myf5-SA and dKO satellite cells at 3 dpi. Yellow arrowheads indicate representative PCNA+ GFP+ cells. Scale bars represent 100 μm (M–P) and 25 μm (Q–T).
See also Figures S2 and S3.