Negative regulation of proneural gene activity: hairy is a direct transcriptional repressor of achaete.

  1. M Van Doren,
  2. A M Bailey,
  3. J Esnayra,
  4. K Ede, and
  5. J W Posakony
  1. Department of Biology, University of California San Diego, La Jolla 92093-0322.

Abstract

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.

Footnotes

| Table of Contents

Life Science Alliance