Figure 1.

MuSCs show a transition in shape as they move from the myoseptum towards the site of injury (asterisk). GFP + muSCs (arrowheads) in uninjured 7 dpf pax7a:egfp larvae are located at the myoseptum (blue box) or in the myotome (yellow outline, a). In the presence of an injury GFP + muSCs at the vertical borders of the myoseptum extend processes into the myotome (b′, arrowheads) and undergo extensive movement along the myoseptum (b). They then stabilize a process extending into the myotome (c′, arrowheads) and detach from the myoseptum (c). Subsequently the GFP + muSCs migrate towards the site of injury, extending processes in multiple directions (d′, arrowheads) as they migrate (d). Quantification of cell responses to injury reveal three phases: extension of cell process, migration and arrival at the injury site (e, n = 28 cells from 6 animals). Scale bar 50 µm (a–d), 20 µm (b′–d′).