PANNIER, A NEGATIVE REGULATOR OF ACHAETE AND SCUTE IN DROSOPHILA, ENCODES A ZINC-FINGER PROTEIN WITH HOMOLOGY TO THE VERTEBRATE TRANSCRIPTION FACTOR GATA-1

The gene pannier acts as a repressor of achaete and scute, two transcr iption factors expressed in discrete subsets of cells at the sites whe re neural precursors develop. Molecular analysis of mutant alleles rev ealed the presence of two functional domains within the pannier protei n: a zinc finger domain showing homology to the GATA-1 family of verte brate transcription factors and a domain comprising two putative amphi pathic hetices. Mutants associated with lesions in the zinc finger dom ain display an overexpression of achaete and scute and the development of extra neural precursors. Mutant proteins in which the domain inclu ding the putative helices is deleted act as hyperactive repressor mole cules causing a loss of achaete/scute expression and a loss of neural precursors. Other results suggest that the activity of pannier may be modulated by association with position-specific factors.