Mmp2 regulates basement membrane remodeling and dedifferentiation of the visceral musculature during Drosophila metamorphosis

The basement membrane (BM) is a specialized extracellular matrix that surrounds most tissues and organs. Remodeling of the BM is critical for morphogenesis and to control tissue homeostasis. During Drosophila metamorphosis, most tissues undergo apoptosis and become histolyzed to be replaced by progenitor cells to generate adult structures, but the visceral musculature trans-differentiates to give rise to new adult muscles. The molecular mechanisms of the BM remodeling during this extensive tissue reorganization are poorly understood. Here, we identified Matrix metalloprotease 2 (Mmp2) as a key regulator of BM remodeling in visceral musculature. We find that Mmp2 is localized when the BM is degraded and that Mmp2 is required for degradation of the major BM components. In addition, Mmp2 is important for survival and tissue metamorphosis. Our results suggests that Mmp2-mediated BM remodeling is a prerequisite for metamorphosis and visceral muscle dedifferentiation.