Fig. 6

Rbfox1l is expressed predominantly in the nucleus and cytoplasm of newly-forming myofibers during skeletal muscle repair. (A) Injury time-course experiment performed in the myog:H2B-mRFP transgenic line showing Rbfox1l expression at each post-injury time-point. (B) myog:H2B-mRFP expression is readily observed within the injury site by 4 dpi. (C) Overlay of Rbfox1l and myog:H2B-mRFP expression. (D) Total number of Rbfox1l, myog:H2B-mRFP double-positive cells at 2–7 dpi in a 75 µm² area within the injury site (to exclude Rbfox1l-positive; myog:H2B-mRFP-positive myonuclei within surrounding uninjured fibers). (E) Ratio of Rbfox1l-positive cells that are myog:H2B-mRFP-positive at 2–7 dpi. One-way ANOVA followed by Tukey's multiple comparisons test was performed for statistical analyses in D and E (p*<0.05; p**<0.01). (F-H) Higher magnification view of 4 dpi injury site shown in A-C. (F'-H') Area shown is the boxed region in F-H. A majority of Rbfox1l-positive nuclei are also positive for myog:H2B-mRFP (examples indicated by white arrowheads), as expected from the extensive overlap of these two markers in differentiated muscle outside of the injury site. Rbfox1l expression in uninjured areas surrounding the injury site appears less uniform in muscle fiber nuclei in this figure (compared to Fig. S6D-D'') as laser intensity was reduced to prevent over-saturation of signals within the injury site. Some newly-forming myofibers that express Rbfox1l in the nucleus and/or cytoplasm are myog:H2B-mRFP-negative (examples indicated by brown arrowheads). Scale bar in all panels is 75 µm.