Worm Breeder's Gazette 11(1): 56a
These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.
Chemosensory neurons fill with fluorescein dyes entering through their exposed receptor cilia and fail to fill when their cilia are too short or the sensillar opening is obstructed. Some mutants with abnormal assembly or degeneration of sensory cilia have been identified by reduced FITC staining (Perkins et al., Dev. Biol. 117, 456 (1986)). In most cases, the defects are confined to sensory structures and, in particular, locomotion is normal. Exceptionally, unc-33 and unc-44 mutants have both dendritic and axonal abnormalities. In addition to having somewhat shortened chemosensory cilia, these mutants are profoundly paralyzed and have numerous defects in axon growth (Hedgecock et al., Dev. Biol. 111, 158 (1985); Desai et al. Nature 336, 638 (1988); S. Siddiqui and J. Culotti, J. Neurosci. ( in press); H. Bhatt, E. Hedgecock, and D. Hall (in preparation)). In a screen for other uncoordinated mutants with reduced FITC-filling, a new unc-101 allele was isolated. In both unc-101(rh6), and in the original unc-101(m1) mutant isolated by D. Riddle, usually only 1 pair of amphid neurons stains brightly (probably ADF) while the phasmid neurons are generally faint or unstained. Amphid cilia are shorter than normal and may be dark and irregular in contour. The AWC cilia fail to spread into wingshaped sheets and the AFD dendrites have an abnormally long cilium but few fingers. The distal specializations of the CEP cilia are also abnormal. Ciliary defects similar to some of these have been reported for che-11, ( Albert et al., J. Comp. Neurol. 198, 435 (1981)). In contrast, the axons of the chemosensory neurons appear to be normal in unc-101 mutants and, to our knowledge, no axonal abnormalities have been reported for other classes of neurons in these strains. Thus unc-101 may represent a new pleiotropic mutant class with both ciliary and motor defects but normal axon growth. The cellular focus of the locomotion defect is unknown.