Regulation of the Drosophila distal antennal determinant spineless

Dev Biol. 2007 Feb 15;302(2):412-26. doi: 10.1016/j.ydbio.2006.09.044. Epub 2006 Oct 3.

Abstract

The transformation of antenna to leg is a classical model for understanding segmental fate decisions in Drosophila. The spineless (ss) gene encodes a bHLH-PAS transcription factor that plays a key role in specifying the identity of distal antennal segments. In this report, we identify the antennal disc enhancer of ss and then use enhancer-lacZ reporters to work out how ss antennal expression is regulated. The antennal determinants Distal-less (Dll) and homothorax (hth) are key activators of the antennal enhancer. Dll is required continuously and, when present at elevated levels, can activate the enhancer in regions devoid of hth expression. In contrast, homothorax (hth) is required only transiently both for activation of the enhancer and for specification of the aristal portion of the antenna. The antennal enhancer is repressed by cut, which determines its proximal limit of expression, and by ectopic Antennapedia (Antp). Repression by Antp is not mediated by hth, suggesting that ss may be a direct target of Antp. Finally, we show that ss+ is not a purely passive target of its regulators: ss+ partially represses hth in the third antennal segment and lies upstream of Dll in the development of the maxillary palp primordia.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Antennapedia Homeodomain Protein / biosynthesis
  • Antennapedia Homeodomain Protein / genetics
  • Drosophila / growth & development
  • Drosophila / metabolism*
  • Drosophila Proteins / biosynthesis*
  • Drosophila Proteins / genetics
  • Enhancer Elements, Genetic*
  • Extremities / growth & development
  • Gene Expression Regulation, Developmental
  • Genes, Reporter
  • Homeodomain Proteins / biosynthesis
  • Homeodomain Proteins / genetics
  • Lac Operon
  • Larva
  • Mutation
  • Pupa
  • Receptors, Aryl Hydrocarbon / biosynthesis*
  • Receptors, Aryl Hydrocarbon / genetics
  • Transcription Factors / biosynthesis
  • Transcription Factors / genetics

Substances

  • Antennapedia Homeodomain Protein
  • Antp protein, Drosophila
  • Drosophila Proteins
  • Homeodomain Proteins
  • Receptors, Aryl Hydrocarbon
  • Transcription Factors
  • distal-less protein, insect
  • hth protein, Drosophila
  • ss protein, Drosophila