Microtubules play complex roles in neuronal development and function, controlling synapse growth and stabilization as well as axon outgrowth and transport. The arsenal of tools that cells have evolved to regulate microtubules include tubulin folding cofactors, microtubule severing proteins, microtubule plus-end binding proteins and multiple classes of proteins that act to stabilize microtubule arrays. Microtubule dynamics and interactions with motor proteins and other microtubule-associated proteins are tightly regulated by the cell, and dysregulation of microtubules and axon transport is part of the pathology of many neurodegenerative diseases. This project uses a molecular genetic approach in C. elegans to study microtubule regulation during nervous system development. The project focuses on the regulation of an alpha-tubulin gene, tba-1, in axon and synapse development. A novel allele, tba-1(ju89), causes synapse loss in the C. elegans GABAergic motor neurons, but does not disrupt early embryonic cell divisions or development. Multiple suppressor mutants (stub genes) were identified through a genetic screen for mutations that reverse the effects of tba-1(ju89) mutation. tba-1(ju89) and the suppressor stub mutants thus provide a unique genetic avenue to study microtubule-mediated mechanisms that are essential for normal synapse and axon differentiation and to identify molecular mechanisms that lead to synaptic dysfunction and neuron degeneration. AIM 1: clone the tba-1(ju89) suppressor stub-1; AIM 2: study the expression of STUB-1 and its colocalization with presynaptic proteins; AIM 3: map stub-2 and stub-3; and AIM 4: test for genetic interactions between the stub genes.
This project will enhance research and education at Occidental College by providing new research opportunities to students in genetics, cell biology and developmental neurobiology and contributing to a new interdisciplinary neuroscience initiative. The presence of a comprehensive C. elegans research program at Occidental will also provide resources and expertise to support the implementation of a new genetics and genomics course and new laboratory modules for the Introductory Cell & Molecular Biology courses using C.elegans RNAi techniques and in vivo imaging of worms expressing transgenic GFP markers.
