Worm Breeder's Gazette 11(1): 39
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.
Temperature-sensitive maternal effect mutations in the emb-5 gene (1) show premature second E cell division and abnormal gastrulation at nonpermissive temperature. Embryos arrest as balls of cells without normal morphogenesis (2). Understanding of the emb-5 gene function at the molecular level should provide a good insight into the mechanism of morphogenesis in animal development. We are trying to clone the emb-5 gene by chromosome walking from Tc1s linked to emb-5 and transformation experiments. We have genetically mapped the emb-5 gene and located it between unc-79 and dpy-17 on linkage group III. To identify Tc1s near the emb-5 gene in Bergerac BO or TR679, we have outcrossed these strains ten times to Bristol N2-derived emb-5 mutant strains doubly marked with unc-79 and dpy-17 or singly with unc-79 and constructed strains with Bristol background except for the region around emb-5. Southern analysis of Tc1-containing restriction fragments for the constructed strains and their parental strains has revealed two Bergerac-associated Tc1s. Three factor mapping has assigned one fragment about 0.28 mu to the left of the emb-5 gene and the other about 0.03 mu to the right. We also found one TR679- associated Tc1-containing fragment closely linked to emb-5, although its map position has not been accurately determined. Using the flanking DNAs of the two Bergerac-associated Tc1s as probes, we have isolated EMBL3 N2 genomic clones. Phage clones corresponding to these Tc1 flanking sequences have been sent to Drs. John Sulston and Alan Coulson, Cambridge, England, for physical mapping.