u-shaped encodes a zinc finger protein that regulates the proneural genesachaete and scute during the formation of bristles in Drosophila

Abstract

The pattern of the large sensory bristles on the notum ofDrosophila arises as a consequence of the expression of theachaete and scute genes. The gene u-shapedencodes a novel zinc finger that acts as a transregulator ofachaete and scute in the dorsal region of the notum. Viable hypomorphic u-shaped mutants display additional dorsocentral and scutellar bristles that result from overexpression ofachaete and scute. In contrast, overexpression ofu-shaped causes a loss of achaete–scute expression and consequently a loss of dorsal bristles. The effects on the dorsocentral bristles appear to be mediated through the enhancer sequences that regulate achaete and scute at this site. The effects ofu-shaped mutants are similar to those of a class of dominant alleles of the gene pannier with which they display allele-specific interactions, suggesting that the products of both genes cooperate in the regulation of achaete and scute.A study of the sites at which the dorsocentral bristles arise in mosaicu-shaped nota, suggests that the levels of the u-shapedprotein are crucial for the precise positioning of the precursors of these bristles.