Ictacalcin is a calcium-binding protein that is found in olfactory receptor neurons in the catfish. This AREA proposal describes a series of experiments aimed at characterizing the ictacalcin gene and the mechanisms underlying its restricted expression to olfactory neurons. Olfactory signal transduction in vertebrates, mediated through G protein coupled pathways, results eventually in fluctuations of cytosolic calcium in the cilia and soma of receptor neurons. Thus, calcium is thought to be involved in signal generation, adaptation and/or termination of the sensory signal. Ictacalcin belongs to the S100 family of calcium binding proteins, the members of which may play a role in mediating the effects of calcium in a variety of other tissues. Because of its tissue-specific expression in the olfactory epithelium, the regulation of the ictacalcin gene is potentially interesting. In this application, Dr. Porta proposes to isolate the full-length ictacalcin gene and initiate a definition of transcriptional elements in its regulatory regions and of cell type specific transcriptional factors involved in its regulation. In the long-term, the P.I. believes that this work has significance for understanding the regulation of chemosensory transduction and other neuronal processes.
