Fig. 4. Reformation of an ECM is also associated with wound healing along the body column. An incision along the body column (at 90° to the longitudinal axis) results in creation of a gap in the ECM (A,C) that is still present 3 hours after wounding, as monitored by whole-mount immunofluorescent staining for laminin (LM) and collagen (Col). The cut edge of the ECM at the wound site is indicated by the arrows in A,C. As observed during head regeneration, the epithelium has already fused by this time (arrowheads in A,C). Upregulation of mRNA occurs 3 hours after wounding (LM shown in E; a similar signal for Col and MMP also occurs, data not shown). Twenty-four hours after wounding, reformation of the ECM has occurred, as monitored with antibody to LM. At this time, a signal for Col is not apparent at this magnification. As with head regeneration, a signal for Col is more easily observed between 24 and 48 hours (data not shown). Upregulation of ECM mRNA continues for 24 hours after wound healing, as monitored for LM (F). Upregulation of Col and MMP mRNA also continues through this time (data not shown). Scale bars: in D, 100 µm for A-D; in F, 200 µm for E,F.