Worm Breeder's Gazette 15(2): 50 (February 1, 1998)
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.
Lab. of Molecular Biology, Toyohashi University of Technology, Tempaku-cho, Toyohashi-441, Japan
Mutants in the unc-119 gene are defective in locomotion, feeding behavior and chemosensation (Maduro M, Pilgrim D,1995). The unc-119 gene expresses in many neurons including the cell bodies and processes of several motor neurons in the nerve cord, pharyngeal region, and in the tail lumbar ganglia, pre-anal ganglion and dorso-rectal ganglion, and the male sensory neurons; suggesting that the unc-119 mutants are defective in most of the nervous system. The expression of unc-119::lacZ and GFP shows that the unc-119 gene is expressed shortly before the comma stage in embryogenesis and continues during late embryonic and post-embryonic development (Maduro M, Pilgrim D,1995). In accompanying abstracts in this issue of WBG, we have shown that the dpy-20 may encode a novel transcription factor that affects transcription of various genes in the ventral cord motor neurons (Ali et al., Shibata et al., Ali et al. see abstracts in this WBG issue ) We have found that in the dpy-20(e2017) mutant background the expression of the unc-119::lacZ is reduced significantly in the ventral nerve cord motor neurons, with little or no affect on the staining pattern of the sensory neurons in the head or tail of the animals. In addition we have observed ectopic expression of the unc-119 reporter gene in the vulval region. These results suggest that the dpy-20 is affecting expression of the unc-119 reporter gene in a select class of motor neurons as there is no effect on the expression of unc-119 in the touch neurons and in the embryos. To test the effect of unc-119 mutation on the expression of dpy-20 gene expression, we have done an experiment in reverse, i.e. studied expression of the dpy-20::lacZ in unc-119(e2498) mutant background and found that there is a small effect of unc-119 mutant background on the expression of dpy-20. In the unc-119 mutant background, about 20% animals show reduced staining in the ventral cord motor neurons and also in the hypodermal cells. To study genetic interaction between the dpy-20 and unc-119 loci, we have constructed a double mutant dpy-20(e2017);unc-119(e2498). The dpy-20( e2017) is an amber allele (J. Hodgkin, 1985), these animals are short in size but their locomotion is quite normal. On the other hand, unc-119(e2498) is an uncoordinated mutant, with abnormal locomotion. Their double mutant is severely paralyze, and it fails to produce eggs and ends up as a bag of worms, and thus shows a reduced brood size. These observations are consistent with a model in which dpy-20 gene mediates transcription of unc-119 gene, particularly in the set of ventral cord motor neurons, but also suggests an additional role in viability and brood size. Staining of the dpy-20 mutant alleles with the nuclear staining dye DAPI reveals that these mutants are also defective in germ line development (M. Y. Ali, Z. K. Siddiqui, and S. S. Siddiqui). We are therefore studying the effect of dpy-20 mutations on various genes which mediate germ cell development. The reporter gene dpy-20::lacZ does not express in the germ line, so we are preparing antibodies made against the DPY-20 protein expressed in E. coli (M. Y. Ali, Z. K. Siddiqui, S. S. Siddiqui, unpublished) to examine the localization of the DPY-20 protein in the wild type and mutant backgrounds. We thank Morris Maduro and David Pilgrim for the unc-119::lacZ line and mutant strains, David Baillie for his help and cooperation and T. Stiernagle for the other mutant strains.