Fig. 4

Fig. 4

Myoblast-like cells, detected using myf5:GFP and myod:GFP transgene expression, are present post-injury in adult zebrafish skeletal muscle. (A) The myod:GFP transgenic line identifies myoblast-like cells at 4 dpi. (A'-A''') Magnified view of boxed area in A, showing myod:GFP expression (A'), EdU incorporation after an acute EdU pulse (A''), and the overlay (A''') at 4 dpi. Double-positive cells are indicated by arrowheads. (B-B''') At 4 dpi, myod:GFP-expressing cells are largely Pax7-negative (examples indicated by arrowheads). (C) Percentage of total proliferating cells (i.e. those that incorporate EdU) at 4 dpi that are Pax7-positive (25%) versus myod:GFP-positive (15%). The percentage of proliferating cells that are Pax7-positive (25%) is similar to that shown in Fig. S3I and is slightly higher than the percentage of proliferating cells that are myod:GFP-positive (15%), although the difference is not statistically significant. (D) Percentage of Pax7-expressing cells at 4 dpi that are myod:GFP-positive (10%) versus myod:GFP-negative (90%), p**<0.01. (E) myf5:GFP-positive cells are present at the injury site at 5 dpi. (E') Magnified view of boxed region in E. (E”) Magnified view of boxed region in E' reveals myf5:GFP-positive cells that are myog:H2B-mRFP-positive (arrowheads). Scale bar in A and E' is 75 µm, in E is 150 µm, and in A'-B''' and E” is 30 µm.