Worm Breeder's Gazette 14(1): 52 (October 1, 1995)
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.
Department of Biology , Johns Hopkins University, Baltimore, MD 21218
Cell fate determination and cell migration are two essential events in the development of animals. mig-5 controls various cell fates and migrations in C. elegans. In mutants of mig-5, the descendants of the QL neuroblast fail to migrate posteriorly but instead migrate anteriorly. Distal tip cells (DTCs) leading the gonad arms make precocious dorsal turns or migrate along abnormal tracks. Also, the DTCs are often absent and occasionally an extra DTC is present. Two anchor cells are sometimes present in the hermaphrodite gonad and two linker cells are usually present in the male gonad. In the vulval equivalence group, secondary vulval precursor cells are often missing, while in the preanal equivalence group, the P12 cell often adopts a P11 cell fate. Between the two alleles of mig-5, rh147 is stronger than rh94 with respect to the DTC lost phenotype. Either maternal or zygotic expression of normal mig-5 is sufficient for wild type phenotype. mig-5 has been cloned by Southern analysis of chromosomal deletions and transgenic rescue experiments. mig-5 is located on cosmid T05C12 in the center of chromosome II. mig-5 is predicted to encode an intracellular protein with 666 amino acids. The protein has three conserved domains that have a high degree of homology to the Drosophila dsh gene product, in addition, the sub-domain B2 has homology with seven other proteins, such as the Drosophila discs large tumor suppresser protein. The homologues of dsh have also been found in several other species, including human. In Drosophila, DSH is a common component in both the wingless and frizzled signal transduction cascades and probably is also involved in the notch signaling pathway. In C. elegans, mig-5 mutants share partial phenotypes with the mutants of the C. elegans homologues of wingless (lin-44), frizzled (lin-17) and notch. (lin-12). Cloning mig-5 makes it possible to study the role of dsh in three important signaling pathways in C. elegans and will lead to a better understanding of the mechanisms of signal transduction in cell fate determination and cell migration.