The Gutzman laboratory applies genetic, developmental, molecular, and cell biological approaches to study brain morphogenesis in the developing embryo and to understand the development of MYH9-Related Disease using zebrafish (Danio rerio) as a model system.
Brain Morphogenesis Project: Mechanisms of Basal Neuroepithelial Tissue Folding
The Role of the Basement Membrane
Morphogenesis requires proper cell shape changes and mechanical force, such as tension. Both of these regulators are known to be mediated by intracellular components, such as the actin and microtubule cytoskeletal networks; however, there is a significant gap in our understanding of how interactions between cells and their extracellular environment, specifically with the extracellular matrix (ECM), function to mediate these morphogenetic processes. The basement membrane is a specific type of ECM found along the basal surface of epithelia and is primarily composed of laminin, collagen, and proteoglycans such as agrin. This matrix was previously regarded as a static scaffold, functioning as a passive structure to mediate cell adhesion and polarity. Now, the basement membrane is emerging as a dynamic network critical for regulating mechanical forces required during morphogenesis. Using the zebrafish midbrain-hindbrain boundary (MHB) as a model system, our research aims to determine how cell shape changes and mechanical forces, such as tension, are mediated by the basement membrane to ensure proper tissue morphogenesis. Our investigation focuses on the individual proteins of the basement membrane to determine their role in modulating cell shape changes and tensile forces required for basal tissue folding.
The Role of Microtubules
Our objective for this research project it to elucidate the microtubule-dependent mechanisms that mediate basal epithelial cell and tissue shape during vertebrate development. Disruption of fundamental cell biological processes, by either genetic mutations or environmental factors, can lead to structural birth defects. It is established that morphogenetic processes depend on the tight regulation of the actomyosin and microtubule cytoskeleton; however, the fundamental mechanisms that regulate cell shape on the basal side of epithelial cells and the mechanistic contribution of microtubules to mediating epithelial tissue morphogenesis remain unknown. Our aim is to to fill this gap by investigating the function of stable microtubules, and the mechanisms by which microtubules are stabilized in vivo during the formation of the highly conserved midbrain-hindbrain boundary (MHB).
MYH9-Related Disease Project
MYH9-Related Disease encompasses a large spectrum of disorders all associated with mutations in the MYH9 gene which encodes for the non-muscle myosin IIA protein. Symptoms of MYH9-Related Disease vary from hematological conditions and kidney problems to deafness and cataracts. Despite a well-supported role for non-muscle myosin IIA in many basic cellular processes, its mechanisms of action and precise function in development of MYH9-Related Disease is unknown. Therefore, the focus of our MYH9-Related Disease project is to understand the role of non-muscle myosin IIA during development of the affected organs. Using CRISPR genome editing, we are generating zebrafish with mutations in the highly conserved myh9 gene that mimic the mutations found in the human population. We will utilize these models to study early embryonic development of affected organs and to begin to elucidate the molecular mechanisms that lead to MHY9-Related Disease.