Worm Breeder's Gazette 16(2): 32
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.
Department of Zoology. University of British Columbia. 6270 University Blvd. Vancouver, BC. Canada. V6T 1Z4
Mutations in the unc-23 gene result in detachment and dystrophy of the anterior body wall musculature and a bent-head phenotype (Waterston et al,1980). Unc-23 is located on linkage group V and is uncovered by the deficiencies, sDf47/71 and mDf1. Using PCR deficiency mapping we determined the breakpoints of these deficiencies and placed unc-23 in a region spanning 12 cosmids (cosmids F28A12 to R03H4). We were able to rescue the unc-23 phenotype using a transgenic strain (kindly provided by A. Schaefer and Dr.M. Nonet) carrying four overlapping cosmids R03H4, F59E11, T19A5, and H14N18. Transgenic strains carrying the first three cosmids failed to rescue unc-23. As an alternative approach we took advantage of some possible deletion and Tc1 alleles of unc-23 to look for polymorphism within the H14N18 interval. We detected two polymorphisms in H14N18.1, one of the four ORFs that we examined using PCR amplification. Two alleles of unc-23, ra801 and ra806 (kindly provided by the Vancouver Reverse Genetics Core Facility) have small deletions (117 and 155 bp, respectively) in the H14N18.1 open reading frame. We consequently sequenced e25 and e324, two EMS alleles of unc-23, and found that e25 is a missense mutation (glutamic acid to lysine) and e324 is a nonsense mutation (glutamine to stop). H14N18.1 encodes a protein most similar to a molecular chaperone regulator known as BAG-2 (BCL2-associated athanogene 2). In humans the BAG family of molecular chaperone regulators contain a conserved 45 amino acid region near their C termini ( the BAG domain) that binds Hsp70/Hsc70 and control their chaperone activity (Takayama et al. 1999). Human and C. elegans BAG-2 share 40% amino acid identity and 62% similarity with each other over the BAG domain and its upstream region.
We are currently sequencing other alleles of unc-23 and attempting to obtain a full length UNC-23::GFP transgenic line to study the spatial and temporal expression pattern of this gene.
REFERENCES:
Takayama, S., Zhihua, X., and Reed, J. (1999). An evolutionary conserved family of Hsp70/Hsc70 molecular chaperone regulators. The journal of biological chemistry 274, 781-786.
Waterston, R. H., Thomson, J. N., and Brenner, S. (1980). Mutants with altered muscle structure in Caenorhabditis elegns. Developmental Biology 77, 271-302.