Worm Breeder's Gazette 9(1): 46
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.
Wild-type animals largely arrest development if L1's are placed on NG plates containing 30 mM or greater concentrations of the methylxanthin-derivative caffeine. Eleven mutants have been isolated among the F2 progeny of EMS-mutagenized animals in which this developmental delay is less severe. Although caffeine delays development in these mutants, most attain adulthood and produce progeny. Wild-type and mutant L1's have been incubated on plates containing between 5mM and 40mM caffeine and their lengths measured after three days. Increasing caffeine concentrations reduced length in a roughly linear fashion. All eleven mutant strains were approximately as resistant as N2, as judged by this criterion. The mutations are recessive and define two new genes, named caf-1 and caf- 2. There are eight alleles of caf-1 and three alleles of caf-2. Linkage testing shows caf-1 is on LGII. It is left of dpy-10 as indicated by a 3F cross using dpy-10 and unc-4. Two factor crosses place it 39 mu away from unc-4 and 21 mu away from sqt-2. You LGII fanatics realize that this is way out in left field. The second gene is right of unc-13, as indicated by a 3F cross using dpy-5 and unc-13. A 2F cross places it approximately 6.7 mu right of dpy-5. This agrees well with observation that caf-2/nDf24 heterozygotes are resistant to caffeine. Caffeine-resistant strains of Escherichia coli are often altered in their lethal responses to UV and ionizing radiations (Grigg, 1967. Mutat. Res. 4, 553; Delvaux and Devoret, 1969. Mutat. Res. 7, 273) . It was hoped a similar situation would exist with C. elegans, thus providing a selection for additional rad mutants. Preliminary inactivation data suggest that this is not the case. We hope to further characterize the mutants by: 1) assaying sensitivities to other methylaxanthin derivatives, including theophylline; 2) constructing a caf-1; utant and determining its sensitivities; and 3) testing for suppression of all alleles by sup-7; and 4) assaying for metabolism of caffeine in N2 and the caf mutants. Suggestions for additional experiments are most welcome.