Implication of Matrix Metalloproteinases One and Two in Autophagic Cell Death in the Drosophila Salivary Gland

Abstract

Programmed cell death plays an important role in normal development. Defects in this process contribute to cancer. Matrix metalloproteinases (MMPs), zinc-dependant endopeptidases that cleave components of the extracellular matrix, are among the multiple protease types implicated in cell death.

Here I provide evidence that MMPs function in <em>Drosophila</em> salivary gland cell death. Misexpression of the MMP inhibitor timp inhibited timely salivary gland cell death, while misexpression of mmp2 induced premature salivary gland cell death. mmp RNA interference was inconclusive because salivary gland persistence observed at 28°C was similar to fkh-GAL4 negative controls. MMPs and caspases might have an additive effect, since misexpression of timp and the caspase inhibitor p35 together enhanced salivary gland persistence compared to either timp or p35 misexpression alone. I also provide descriptive confocal microscopy of wild-type salivary glands using ?-Spectrin and the polarity marker Crumbs which suggest that polarity is lost during salivary gland cell death.