Fig. S1

Induction of matrix metalloproteinase 9 (mmp9) expression by copper treatment in zebrafish larvae. In situ hybridization to detect expression of mmp9 was carried out in control (a and c) and sibling fish treated with copper sulfate (c and d). (a and b) Induction of mmp9 expression after treating 2-day-old fish with 10 μM CuSO₄ for 40 minutes. While control fish have few detectable cells labeled with probe, clusters of highly labeled cells are seen in a characteristic pattern along the flanks of the treated animals. The inset shows a closeup image of one of these clusters. (c and d) mmp9 induction by treatment of 3-day-old fish with 100 μM CuSO₄ for 6 hours and fixed immediately thereafter. Note that clustering of labeled cells at discrete positions along the midline is also apparent after the more severe treatment.