Fig. 3

Fig. 3 Mmp2 is activated in the notochord and EVL shortly after the onset of somitogenesis. Epifluorescence and bright field imaging of early somitogenesis embryos expressing EMMA-Mmp2 (A,B) and whole mount immunostains (C?E) at 4 hpHS. EMMA-Mmp2 is expressed in response to heat shock embryos during early somitogenesis in both embryos at 1?2 somites (A) and embryos of 5?8 somites (B). Expression is prominent anteriorly (I) and in the notochord (II). EMMA-Mmp2 is not activated in 1?2 somite embryos (C), but is activated in 3?8 somite embryos (D) in the EVL (D) and notochord (D?, D?). Localization and activation of EMMA-Mmp2 in the EVL occurs in a patchwork pattern (D). The lowest amount of activation is found in the mesoderm (V) and the highest in the notochord (VI). Signal to noise ratio in the EVL decreases with time post heat shock, but patterns remain similar. Calibration bar at the right relates the heat map to the extent of activation, with H indicating high levels of activation (GFP/(GFP ?+ ?HA) ratio approaching 1), and L indicating low levels of activation (GFP/(GFP ?+ ?HA) ratio approaching 0). The patterns of activation illustrated were consistent in all embryos imaged at this stage (n ?= ?3).