Markers for neuronal cilia.

Primary cilia were first detected on neurons in the mammalian brain over 40 years ago using electron microscopy. However, this approach is very labor intensive and has inherent limitations that restrict its utility for studying neuronal cilia. While the study of cilia in other tissues was greatly facilitated by the identification of specific ciliary markers, historically there have been no markers for neuronal cilia. Fortunately, recent developments make the study of neuronal cilia more practical. First, specific proteins have been shown to selectively localize to neuronal cilia and can serve as markers by immunolabeling. Second, neurons have been shown to possess cilia in culture, which allows for the use of additional approaches, such as live-cell imaging of neuronal cilia. This chapter provides an overview of the current techniques for visualizing neuronal cilia in tissue as well as fixed and living cells. These approaches allow for the identification of additional neuronal ciliary proteins and provide a basis for future functional studies.