RUI: Investigating the pathways and regulation of lysosome-related organelle biogenesis.

The project will discover how intracellular compartments are formed during embryonic development. Animal cells contain compartments called organelles that often gives individual cells their specialized function. One of these compartments, called a lysosome-related organelle (LRO), mediates important activities, including the creation of body pigments, the storage of nutrients, and signals for aging.

This project will discover when these organelles are first created during animal development, investigate how material is directed to these compartments, and study how their number and size are regulated. Each year, 30-40 undergraduates will be mentored in collaborative, investigative, and original research as part of the project. The project will provide hands on scientific training for a large and diverse group of students, most of who will likely progress on to careers in science and education.

Little is currently known about how the trafficking pathways to LROs emerge during cellar differentiation, whether endolysosomes, such as late endosomes or lysosomes, function in LRO protein delivery, and how biogenesis pathways are regulated to control LRO number and size. To investigate these processes, this project analyzes the biogenesis of gut granules, LROs found in C. elegans intestinal cells.

The research will use genetic approaches to examine whether LRO biogenesis genes function in the germline or embryo, and after determining when LRO proteins are first made during development, evaluate their distribution relative to endosomal organelle markers using quantitative fluorescence microscopy. In addition, whether gut granule cargo is routed through endolysosomes will be using pulse chase and add-back approaches, as well as live-cell fluorescence imaging of interactions between endolysosomes and gut granules.

When pathways directing LRO protein trafficking are active will be determined by tracking gut granule cargo following its targeted expression at different stages of development combined with newly developed methods to potently disrupt the function of LRO biogenesis proteins. Finally, a collection of C. elegans mutants with enlarged gut granules will be assessed to identify potential regulators of LRO homeostasis.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.