ECTOPIC EXPRESSION OF EITHER THE DROSOPHILA GOOSEBERRY-DISTAL OR PROXIMAL GENE CAUSES ALTERATIONS OF CELL FATE IN THE EPIDERMIS AND CENTRAL-NERVOUS-SYSTEM

Previous studies have shown that the segment polarity locus gooseberry , which contains two closely related transcripts gooseberry-proximal a nd gooseberry-distal, is required for proper development in both the e pidermis and the central nervous system of Drosophila. In this study, the roles of the gooseberry proteins in the process of cell fate speci fication have been examined by generating two fly lines in which eithe r gooseberry-distal or gooseberry-proximal expression is under the con trol of an hsp70 promoter. We have found that ectopic expression of ei ther gooseberry protein causes cell fate transformations that are reci procal to those of a gooseberry deletion mutant. Our results suggest t hat the gooseberry-distal protein is required for the specification of naked cuticle in the epidermis and specific neuroblasts in the centra l nervous system. These roles may reflect independent functions in neu roblasts and epidermal cells or a single function in the common ectode rmal precursor cells. The gooseberry-proximal protein is also found in the same neuroblasts as gooseberry-distal and in the descendants of t hese cells.