The ABCs of Gene Cloning

Abstract

The egl-46 gene is required for the correct differentiation of the HSN neurons, a pair of motor neurons necessary for egg-laying (1,2). In addition, an extra pair of touch receptor-like cells is present in egl-46 mutant animals (3). This finding led to the hypothesis that egl-46 represses touch cell fate in these cells. We have cloned the egl-46 gene using transformation rescue and we have confirmed the assignment by identifying the mutations present in the four known egl-46 alleles. A 5.5kb fragment of CO9E6 partially rescues the Egl phenotype of egl-46 animals. The egl-46 gene (K11G9.4) encodes a C2H2 zinc finger protein that contains three putative zinc fingers. We have confirmed the exon-intron structure of egl-46 by sequencing a cDNA and by 5' RACE analysis. egl-46::lacZ and egl-46::GFP reporter constructs are expressed in a complex pattern which includes cells in the head, tail and ventral cord. We are now trying to determine the identity of the staining cells. Future work will address the mechanism by which the egl-46 gene controls neuronal fate and/or differentiation. (1) Desai, C., Garriga, G., McIntire, S.L. and H.R.Horvitz (1988) Nature 336, 638-646. (2) Desai, C. and H.R.Horvitz (1989) Genetics 121, 703-721. (3) Mitani, S., Du, H., Hall, D.H., Driscoll, M. and M. Chalfie (1993) Development 119, 773-783.