Worm Breeder's Gazette 15(3): 34 (June 1, 1998)
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.
Institute of Molecular Biology and Biochemistry, 8888 University Dr., Simon Fraser University Burnaby, B.C., V5A 1S6, Canada
Our lab is interested in correlating essential genes with cosmids located on chromosome III. To this end we have rescued a number of essential genes using transformation rescue in the area covered by sDf 125 and sDf 127 (Janke et al 1997). We reported in this paper that let-767 was rescued by cosmid C31H11. Further rescues have localized let-767 to C56G2.6 which overlaps with C31H11. It is 55% similar to human estradiol 17-bdehydrogenase 3 over 239 amino acids.
We have isolated three separate alleles for let-767 all of which block at different stages (early, mid or late larval). s2176 blocks at an early larval stage, s2819 at mid-larval, and s2464 blocks at a late larval stage. A screen for essential genes in a ncl-1 background isolated s2819 in order to facilitate mosaic analysis. We are currently performing mutational analysis on each of these alleles. The mutation in the early larval blocked s2176 animals is a change in a well conserved Gly residue to Arg. This specific glycine residue is conserved among all C. elegans and human homologues. In addition to muation analysis we were interested in the expression pattern of let-767. We have made a GFP fusion construct with C56G2.6 and have shown it to be heavily expressed in the gut (thanks to Dr. Fire for his vector kit)
In addition to C56G2.6, there are at least four other homologues in C. elegans all located on chromosome V ( please see table below) We plan to construct GFP fusion proteins with each of the other homologues to see if there is a differential expression pattern. We are also going to attempt to rescue let-767 with the other forms under the expression of the let-767 promoter.
Janke, D. L. et al. (1997) Interpreting a Sequenced Genome: Toward a Cosmid Transgenic Library of Caenorhabditis elegans.Genome Research 7974-7985.