Worm Breeder's Gazette 7(1): 88
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.
We have been using a simple scheme to isolate sup-7(st5)- suppressible lethals near dpy-10 II. We chose this region because some of the interesting temperature-sensitive lethals are near dpy-10, but the scheme should be generally applicable to any autosomal region. Our immediate goal is to find and characterize amber mutants affecting early embryogenesis; we also hope to find null alleles of genes defined by ts alleles. The method is to mutagenize dpy-10 II;unc-6 X hermaphrodites and mate them with sup-7 X/0 males; unc-6 is closely linked to sup-7, and neither dpy-10(e128) nor unc-6(e78) is suppressed by sup-7. Individual F1's are put on separate plates and allowed to self- fertilize. Broods that have Dpy's and Unc's, but no Dpy Unc's are candidates for mutants that carry a suppressed nonmaternal lethal linked to dpy-10. To look for suppressed steriles and maternal-effect lethals, we pick Dpy's, Unc's, and Dpy Unc's from each brood that has them. If the stock carries a linked suppressible lethal, then both the Dpy's and Unc's will be fertile, while the Dpy Unc's, homozygous for the lethal mutation and lacking sup-7, will be sterile. The Dpy's are picked to maintain a homozygous mutant stock that has at least one copy of sup-7. All candidates are backcrossed at least twice and outcrossed at least once to rol-5 II;unc-6. So far, we have screened about 700 F1's and found 3 mutants; several other candidates are still being cleaned up. One mutant is nonmaternal and the other two show a maternal effect; of these two, one is male rescuable and one is not. All three are maintained as sup- 7 homozygotes; the mutants are suppressed poorly by one copy of the suppressor; no lines that segregated Dpy Unc's could be maintained. This scheme seems to be an effective way to isolate amber mutants in autosomal essential genes. Such mutants are found at a fairly high frequency in the dpy-10 region.