A GENETIC-ANALYSIS OF THE DROSOPHILA CLOSELY LINKED INTERACTING GENESBULGE, ARGOS AND SOBA

The Drosophila gene argos encodes a diffusible protein that acts as a negative regulator of cell fate decisions. To define interacting gene products, we performed a genetic analysis of argos, which suggests the presence of several partially redundant gene functions in its immedia te vicinity at the chromosomal position 73A. Dose titration experiment s have identified two of these loci. One of them corresponds to the ge ne bulge. Loss of function bulge alleles suppress the rough eye phenot ype associated with overexpression of argos; conversely, amorphic argo s mutations suppress the eye phenotype seen in flies bearing a single dominant bulge allele. Recombination mapping localized bulge 0.15 cM d istal to argos. A second gene, suppressor of bulge and argos (soba), c orresponds to the recently described lethal complementation group 73Aj . soba alleles suppress the eye phenotypes seen in flies expressing ei ther the dominant bulge allele or the hs-argos construct. soba resides 120 kb proximal to argos. In addition, we have identified one allele of a new gene, clown, which like soba suppresses the eye phenotypes as sociated with hs-argos and bulge(Dominant). clown maps on chromosome 3 at the cytological position 68CD.