Negative regulation of proneural gene activity: hairy is a direct transcriptional repressor of achaete.
hairy (h) acts as a negative regulator in both embryonic segmentation and adult peripheral nervous system (PNS) development in Drosophila. Here, we demonstrate that h, a basic-helix-loop-helix (bHLH) protein, is a sequence-specific DNA-binding protein and transcriptional repressor. We identify the proneural gene achaete (ac) as a direct downstream target of h regulation in vivo. Mutation of a single, evolutionarily conserved, high-affinity h binding site in the upstream region of ac results in the appearance of ectopic sensory organs in adult flies, in a pattern that strongly resembles the phenotype of h mutants. This indicates that direct repression of ac by h plays an essential role in pattern formation in the PNS. Our results demonstrate that HLH proteins negatively regulate ac transcription by at least two distinct mechanisms.
Department of Biology, University of California San Diego, La Jolla 92093-0322.
M
M
Van Doren
A M
AM
Bailey
J
J
Esnayra
K
K
Ede
J W
JW
Posakony
D000818:Animals; D001483:Base Sequence; D004268:DNA-Binding Proteins; D004330:Drosophila / Q000235:genetics*; D005786:Gene Expression Regulation; D017344:Genes, Insect; D018257:Helix-Loop-Helix Motifs; D008969:Molecular Sequence Data; D009154:Mutation; D017933:Peripheral Nervous System / Q000196:embryology*; D012097:Repressor Proteins; D014158:Transcription, Genetic
D004268:DNA-Binding Proteins; D012097:Repressor Proteins