The nervous system relies on specialized sensory neurons to sense environmental conditions and initiate appropriate physiological and behavioral responses. Functions of many sensory neurons are dependent on the presence of morphologically specialized cilia which are microtubule-based organelles acting as cellular 'antennae'. A mechanism called intraflagellar transport (IFT) is required to build cilia and transport cargo and ciliary precursors into the ciliary compartment. However, little is known about how diverse, specialized sensory cilia are shaped. Caenorhabditis elegans is an established model for the study of cilia generation and maintenance. Worms possess 60 ciliated neurons, each of which is specialized to sense specific cues. The BAGL/R sensory neurons, so-called due to the bag-like appearance of their cilia, sense carbon dioxide and decreases in oxygen levels. Little is known about the mechanisms by which BAG cilia are formed, although interestingly, the essential IFT component
osm-6/IFT52 has been reported not to be expressed in the BAG neurons. To investigate the formation of BAG cilia, I am first analyzing BAG cilia structure in known ciliary mutant backgrounds to determine the extent to which BAG ciliogenesis depends on known ciliary genes. I am analyzing in vivo IFT as well as the ultrastructure of BAG cilia in wild-type animals, and plan to carry out a forward genetic screen to identify new genes required for BAG ciliogenesis. Comparing the pathways for BAG cilia specialization to those of other specialized C. elegans neuronal cilia will allow me to define new mechanisms for the generation of ciliary structure diversity.