CONICET | Buscador de Institutos y Recursos Humanos

The extracellular matrix (ECM) is an intricate arrangement of glycoproteins, collagens, proteoglycans and growth factors that act not only as a physical scaffold for the attachment and organization of cellular structures, but also as a mediator of intracellular signaling through cell surface receptors that recognize them. SPARC is a 42 kDa ECM component which regulates cell-shape, adhesion, proliferation, migration and differenciation. Although the biology of mammalian SPARC has been studied extensively, no receptors have been identified so far. For this reason we tried to elucidate the identity of SPARC receptor and its associated signaling pathway using the D melanogaster model. This biological model shows extensive conservation of the main ECM components in the context of a smaller gene number. To carry out this project, we generated several UAS transgenic lines and used them to overexpress dSPARC in spatially and temporally restricted patterns. Ubiquitous or mesoderm-ectoderm specific overexpression produced phenotypes likely related to migration and adhesion failures, namely germ band retraction, dorsal closure and denticle-belts pattern. We have observed similar phenotypes studying chromosomal deficiencies that include the SPARC locus, as confirmed by single-embryo PCR. Our results are consistent with a model in which either increased or decreased activity of SPARC leads to defects in cell adhesion and migration.

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