Figure 3.

SRSF1 Is Indispensable for Postnatal Satellite Cell Proliferation In Vivo and In Vitro

(A) Hindlimb and DIA muscles from P1 control and MKO mice was prepared and stained for MyoD (red), and merged images with DAPI (blue) and laminin (gray) are shown on the right. Quantification of MyoD⁺ nuclei between control and MKO animals is shown on the right histogram. Error bars depicted mean ± SEM (n = 3). Scale bar, 50 μm.

(B) Brief diagram of EdU in vivo labeling and detection on the top. EdU detection and calculation in labeled hindlimb muscles and DIA muscles on the bottom. EdU was detected by labeling with Alexa 488 (green) and nuclei were stained with DAPI (blue), proliferating satellite cells were labeled with PAX7 (red). Error bars depicted mean ± SEM (n = 3). Scale bars, 50 μm (or 20 μm enlarged).

(C) Satellite cells were purified from P6 control and MKO mice using FACS, and cultured in growth medium in vitro. Representative microscopic images of control and MKO satellite cells at culture day 0 and day 4 were shown. Growth curve is shown on the right (n = 3).

(D) Single EDL myofibers were isolated from P8 control and MKO mice. Myofibers were plated on Matrigel-coated dishes and cultured in proliferation medium. Representative bright-field pictures are shown at the indicated times (n = 3). Scale bar, 50 μm.