Mmp2 as a Regulatory Target of ßftz-f1 in Drosophila melanogaster Larval Fat Body Remodeling

Abstract

Tissue remodeling is an important process by which cells dissociate and detach from one another. This phenomenon is involved in both healthy and disease driven functions in the human body including wound healing, and cancer metastasis. Tissue remodeling is carried out in part by Matrix Metalloproteinases (MMPs), proteases that cleave bonds in extracellular matrix (ECM) allowing cells to dissociate and detach from one another, enabling them to move to new locations. Due to the potentially dangerous actions of Mmps, their expression is tightly regulated. Drosophila melanogaster is a useful model organism for studying tissue remodeling and the regulation of Mmp expression through the examination of larval fat body remodeling. Drosophila larval fat body remodeling occurs during the transition from larva to adult fly. It is a tightly regulated process believed to involve the MMP Matrix Metalloproteinase 2 (MMP2). MMP2 is thought to cleave fat cell ECM proteins allowing cells to detach from each other in the process of remodeling. Previous research suggests that Mmp2 expression in Drosophila is regulated by a ßFTZ-F1-mediated, 20-hydroxyecdysone (ecdysone) hormonal cascade (Bond et al. 2011). Both ßftz-f1 and Mmp2 have been demonstrated as necessary and sufficient to induce Drosophila larval fat body remodeling (Bond et al. 2011). This study investigates the hypothesis of Mmp2 as a downstream regulatory target of ßFTZ-F1 as a part of an ecdysone hormonal cascade in Drosophila larval fat body remodeling. Specifically, I hypothesize that ßFTZ-F1 induces Mmp2 expression. Investigations were carried out through relative quantification of Mmp2 (as compared to a control gene) expression in wild type Drosophila fat body as compared to fat body in which ßftz-f1 expression has been reduced. I expected reduced expression of Mmp2 in ßftz-f1-reduced fat body as compared to wild type fat body. If Mmp2 expression is indeed induced by ßftz-f1 expression, a reduction in ßftz-f1 expression will result in a corresponding reduction in Mmp2 expression. Findings demonstrated a reduction in Mmp2 expression in ßftz-f1-reduced fat body aged 10 hours after puparium formation (APF). These results are consistent with the hypothesis that Mmp2 expression is induced by ßftz-f1 expression. Findings also demonstrated an increase in Mmp2 expression in ßftz-f1-reuced fat body aged 8 and 12 hours APF. These results are counter to the hypothesis. Because only one trial has been done, these results are highly preliminary.