Worm Breeder's Gazette 17(1): 43 (October 1, 2001)
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.
| 1 | International Institute of Genetics and Biophysics, CNR, 80125 Napoli |
| 2 | The Hubrecht Laboratory, 3584 CT Utrecht |
We have previously described the isolation, after EMS mutagenesis, of a series of mutants that have lost the ability to avoid the water soluble repellent quinine hydrocloride (qui mutants=QUInine non-avoiders).
Five mutants presented an unaltered response to light touch and a wild-type structure of the sensory cilia when stained with the fluorescent dye DiO. One of them, qui-1 (gb 404) showed very low avoidance of quinine and SDS although its avoidance responses to high osmotic strength and Cu++ appear unchanged. We cloned qui-1 using the SNPs mapping strategy (Wicks et al. 2001). Initially, we positioned qui-1 in a small interval on the LG IV of about 120 kb, between the two SNPs Y45F10A and C08F11A. Then, we rescued the quinine avoidance mutant phenotype by injecting long wild-type PCR products in the qui-1 (gb404) strain. The smallest rescuing fragment was 11 kb and contained a single gene Y45F10B.10, predicted by the C.elegans genome-sequencing consortium. We then sequenced the complete Y45F10B.10 gene in the qui-1 (gb404) strain and found a CAA to TAA transition that generates a stop codon in the first exon. The locus can in principle produce a truncated protein of only 76 aa which presumably has no function. The results obtained in the rescue experiments and those of the sequence of the qui-1 (gb404) indicate that qui-1 corresponds to Y45F10B.10.
BLAST search results revealed that QUI-1 is a novel protein of unknown function that contains four WD 40 domains described as functional modules for protein-protein interaction. However the cellular function of QUI-1 cannot, at present, be inferred from its amino acid sequence.
Using different GFP fusion constructs we discovered that qui-1 is expressed in a subset of the sensory neurons of the amphid including ASH, ADL that have been previously identified as water soluble avoidance neurons. Using GFP constructs with the entire gene we found that the localization of the protein is not confined to the sensory cilia instead the GFP is diffuse in the cell body, the dendrite, sensory cilia and axon.
References:
Wicks SR, Yeh RT, Gish WR, Waterston RH, Plasterk RHA. (2001). Rapid gene mapping in Caenorhabditis elegans using a high density polymorphism map. Nature Genetics 28: 160-164.