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Fig. 6
Partial contribution of clones to wound repair in zebrafish muscle. (A) Schematic of wounding procedure (modified from Kimmel et al., 1995). A small needle wound was made near to marked mnc in somite 14 (som14) in the epaxial region of two adjacent somites at 4 dpf (B-G) or epaxial region of som16 at 3 dpf (H-K). Anterior to left, dorsal up. For clarity, short confocal stacks including the marked mnc are shown (B-G) extracted from full somite stacks before (B,C) and after (D-G, H-K) wounding. (B,C) Superficial (B) and deeper (C) images before wounding. Distinct fibres present different colours after limited recombination at an early stage, thereby allowing unambiguous identification of the region (white arrowhead, white dot). A single EYFP-marked mpc (arrow) in som14 identified shortly prior to wounding. Note the presence of red (asterisk) and bright (arrowhead) and dim (dot) yellow fibres. (D) By 2 h post-wounding (hpw), and despite dimming caused by the wounding procedure, the marked mnc (arrow) and the yellow fibres (arrowhead and dot) perdure in the wounded region (outlined by dashed line). In contrast, the red and bright yellow fibres have been lost. (E) At 1-day post-wound (dpw), fluorescent signal has recovered and several bright EYFP-marked cells are detected in the wounded region (arrows). (F) By 2 dpw, EYFP-marked cells are larger and elongating parallel to fibres (arrow) and present in adjacent unwounded somite (red arrowhead). (G) At 3 dpw, the clusters of EYFP-marked mncs are replaced by several EYPF-marked fibres (arrows), indicating the extent of clonal contribution to the regenerate. Note the limited clonal expansion of the EYFP-marked clone over the 3-day period and the absence of label between the marked fibers (blue arrowheads). (H-K) A second example showing single optical slices, with landmarks identifying wounded somites (white dot and asterisk) and tracking repair of a single fibre by fusion of cells from EYFP-marked (yellow arrows) and mCer/marked (cyan arrows) mpcs. Rapid purse-string epidermal wound closure is visible 1 hpw (arrowhead). Scale bars: 50 µm.