Rashna Sharmin / Biology / Faculty Mentor: Piya Ghose
Morphologically complex cells, defined by their elaborate processes, such as neurons bearing axons and dendrites. How complex cells are eliminated is poorly understood. Intracellular transport is especially important for morphologically complex cells yet its role in cell elimination is underexplored. We discovered a novel ‘tripartite’ killing program that dismantles the sex-specific CEM neurons and the morphologically complex tail-spike epithelial cell during C. elegans embryonic development. This program, we term Compartmentalized Cell Elimination, or CCE, where three cell regions dying in different ways. Remarkably, the single process of these cells shows two disparate elimination morphologies in two subcellular domains, morphologically similar to different types of developmental pruning and retraction. We present CCE as a powerful in vivo model for region-specific cell elimination. We report that mitochondrial retrograde transport, mediated by the Kinesin-1 homolog UNC-116, and soma sequestration of mitochondria are a pre-requisite for CCE. Our genetic evidence suggests that soma confinement of mitochondria is accomplished by the targeting of the anterograde motor UNC-104/Kinesin-3 by CED-3/Caspase. Our findings present a regulatory mechanism for the novel phenomenon of CCE, introduce a novel, in vivo, caspase target and provide insight into regulation of pruning/localized cell elimination as well as neurodegenerative diseases.
Leave a Reply