An analysis of basement membrane repair in vivo
Ramos-Lewis, William David
Basement membranes are sheet-like extracellular matrixes that can be found on the basal surface of epithelial and endothelial cells, surrounding muscles and other organs, and in association with neurons. In addition to providing structural support for associated cells, basement membranes influence cellular behavior and differentiation via interactions with cell surface receptors and by regulating the diffusion of secreted signaling molecules. Upon sustaining an injury, the basement membrane of a damaged tissue is repaired as a part of the wound healing process. However, though details of de novo basement membrane assembly have been studied extensively, very little is known about basement membrane repair. The experiments discussed in this dissertation reveal that basement membrane repair in Drosophila larva epidermis results in a scar-like lesion that is characterized by increased deposition of basement membrane in a fibrous-like pattern. It is composed of all four of the core basement membrane proteins (laminin, collagen IV, perlecan, and nidogen). Additionally, basement membrane proteins that are incorporated into the scar originate from the same cells as basement membrane that is incorporated into undamaged regions. Finally, requirements for basement membrane repair differ from de novo assembly. While de novo basement membrane assembly requires laminin for all other components to be incorporated, only nidogen requires laminin during wound repair.