Worm Breeder's Gazette 12(3): 64 (June 15, 1992)
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.
A number of loci have been identified that are required for proper germ-line development in C. elegans. The mes-3 locus, identified by five mutant alleles, shows a strict maternal-effect sterile or "grandchildless" phenotype (Capowski et. al. Genetics 129: 1061-1072). The main defect observed in progeny of mutant mothers is a severe reduction in postembryonic germ-line proliferation.
To better understand the role of mes-3 in germ-line development, we have initiated cloning and molecular characterization of the gene. mes-3 maps between unc-38 and , dpy-5 ,a region spanned by a contig. We have been taking two approaches toward cloning mes-3 :defining a smaller interval which contains mes-3 and transformation rescue using YACs and cosmids.
To establish a leftward boundary, we used the polymorphism mapping technique described by H. Browning (WBG vol. 12 #2) to map the endpoint of hDf6 .a deficiency that uncovers unc-38 ,but does not uncover mes-3 or dpy-5 ,to the cosmid F14A9 .A rightward boundary for the mes-3 region was established by Bristol/Bergerac polymorphism mapping. The cosmid C30F8 detects Ava I and Hinc II polymorphisms between the two strains. Recombination mapping of these polymorphisms relative to unc-73 , mes-3 .and dpy-5 ,placed them to the right of mes-3
We have obtained transformation rescue of mes-3 with the YACs Y55F5 and Y72E2 ,and more recently with the cosmid B0231 .Using B0231 as a probe, we were able to detect polymorphic fragments (EcoR I, Hind III, and Sst I) in Southern analysis of the mutant allele bn35 .
To narrow down the mes-3 -containingregion, we are currently screening for phage that hybridize with B0231 and attempting rescue with restriction fragments of B0231 .
H. Browning (WBG vol. 12 #2)