Worm Breeder's Gazette 15(1): 71 (October 1, 1997)
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, Technion-Israel Institute of Technology Haifa 32000, Israel.
We are interested in mechanisms of cell adhesion and cell fusion. Cell fusion in humans occurs during fertilization and during the development of multinucleate cells that are contained in bones, muscles and placenta. In C. elegans there are cell fusions during the formation of the vulva, pharynx, uterus, excretory gland and in the hypodermis. There are 46 multinucleate cells (1) of which hyp7 is the largest (133 nuclei).Hpy 7 is part of the hypodermal envelope that surround the adult worm. In a screen for mutations that are affected in the process of cell fusion many mutants were found and analyzed. The mutations were sorted into two main groups: hyperfusion and disordered hypodermis (1). No mutants with fewer fusions in the hypodermis were identified (hypofusion). duf-1(zu316cs) is a dorsal unfused zygotic lethal mutation that was isolated in a screen for mutants affected in the process of elongation (2). The phenotype was analyzed by immunofluoresence using the MH27 antibody. The MH27 protein is expressed in the adherens junctions at the apical domain of the hypodermis and it enable us to follow the fusions between hypodermal cells. After outcrossing we found that zu316cs is a cold sensitive mutation, at 15!C embryonic elongation arrests between 1.5 to 2 fold with fewer fusions in the dorsal hypodermis (hyp6 and hyp7) compared to the wild type and the tail is twisted (3). At 25!C some embryos arrest at 1.5 to 2 fold with fewer dorsal fusions, most embryos arrest at 3 fold and many hatch with normally fused hyp7 and variable posterior defects. duf-1 was mapped to the X chromosome, 10 centiM away from lon-2 (e678). Viral induced cell fusion and invasion by enveloped viruses are cold-sensitive processes. Many cold-sensitive mutations in different fusogenic viral proteins have been analyzed. Our characterization of duf-1(zu316) is consistent with the idea that membrane fusion is a cold-sensitive process. The future plans are to further characterize the phenotypes at the permissive and restrictive temperatures, find the cold sensitive period and to continue the mapping. 1. Podbilewicz B.(1997) Worm Meeting Abstract, p.300 2. Costa M. and Priess J.(1995) Worm Meeting Abstract, p.165 3. Gattegno T. and Podbilewicz B.(1997) Worm Meeting Abstract, p.546 We thank Mike Costa and Jim Priess for sending zu316 to us.