Figure 2.

JNK-dependent expression of Mmp1 in ras^V12, scrib^−/− tumors. Third instar eye/antennal imaginal discs carrying GFP-marked clones (green) of the indicated genotypes were immunostained with an anti-Mmp1 antibody (red) and analyzed by confocal microscopy. (A) Strong upregulation of Mmp1 protein expression in ras^V12, scrib^−/− clones is seen not only in overgrown eye/antennal discs but also in cells invading distal parts of the brain such as the VNC (A, right). Magnification of the VNC with invading Mmp1-positive cells (A′). Mmp1 protein is enriched on surface of malignant ras^V12, scrib^−/− cells (A″). (B) Mmp1 expression is lost when JNK activity is suppressed by the expression of Bsk^DN in ras^V12, scrib^−/− clones. Note that the clonal tissue still overgrows the entire eye/antennal imaginal disc. (C–E) While significantly smaller, scrib^−/− clones show prominent Mmp1 staining (D) compared to the bigger wild-type control (E) or ras^V12 (C) clones. (F, G) Mmp1 expression in scrib^−/− clones is lost when JNK signaling is suppressed by Bsk^DN (F) or when Fos function is inhibited by RNAi (G) in these clones. Note that the scrib^−/− clones grow bigger in size when their JNK activity is suppressed. (H) Activation of the JNK pathway by Hep^act is sufficient to induce Mmp1 expression in ras^V12 clones that have normal scrib function. Except for the images in (A–A″), which are single confocal sections, all other panels show projections of multiple sections. Scale bars=50 μm in (A, A′, B–H) and 10 μm in (A″).