Structural rules and complex regulatory circuitry constrain expression of a Notch- and EGFR-regulated eye enhancer

Dev Cell. 2010 Mar 16;18(3):359-70. doi: 10.1016/j.devcel.2009.12.026.

Abstract

Enhancers integrate spatiotemporal information to generate precise patterns of gene expression. How complex is the regulatory logic of a typical developmental enhancer, and how important is its internal organization? Here, we examine in detail the structure and function of sparkling, a Notch- and EGFR/MAPK-regulated, cone cell-specific enhancer of the Drosophila Pax2 gene, in vivo. In addition to its 12 previously identified protein-binding sites, sparkling is densely populated with previously unmapped regulatory sequences, which interact in complex ways to control gene expression. One segment is essential for activation at a distance, yet dispensable for other activation functions and for cell type patterning. Unexpectedly, rearranging sparkling's regulatory sites converts it into a robust photoreceptor-specific enhancer. Our results show that a single combination of regulatory inputs can encode multiple outputs, and suggest that the enhancer's organization determines the correct expression pattern by facilitating certain short-range regulatory interactions at the expense of others.

Publication types

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

MeSH terms

  • Animals
  • Animals, Genetically Modified
  • Base Sequence
  • Binding Sites / genetics
  • DNA / genetics
  • DNA-Binding Proteins / genetics*
  • DNA-Binding Proteins / metabolism
  • Drosophila / genetics*
  • Drosophila / growth & development*
  • Drosophila / metabolism
  • Drosophila Proteins / genetics*
  • Drosophila Proteins / metabolism*
  • Drosophila melanogaster / genetics
  • Drosophila melanogaster / growth & development
  • Drosophila melanogaster / metabolism
  • Enhancer Elements, Genetic
  • ErbB Receptors / genetics
  • ErbB Receptors / metabolism*
  • Evolution, Molecular
  • Eye / growth & development*
  • Eye / metabolism
  • Eye Proteins / genetics*
  • Eye Proteins / metabolism
  • Gene Expression Regulation, Developmental
  • Genes, Insect
  • MAP Kinase Signaling System
  • Molecular Sequence Data
  • Mutagenesis
  • PAX2 Transcription Factor / genetics
  • PAX2 Transcription Factor / metabolism
  • Photoreceptor Cells, Invertebrate / cytology
  • Photoreceptor Cells, Invertebrate / metabolism
  • Receptors, Invertebrate Peptide / genetics
  • Receptors, Invertebrate Peptide / metabolism*
  • Receptors, Notch / genetics
  • Receptors, Notch / metabolism*
  • Sequence Homology, Nucleic Acid

Substances

  • DNA-Binding Proteins
  • Drosophila Proteins
  • Eye Proteins
  • N protein, Drosophila
  • PAX2 Transcription Factor
  • Receptors, Invertebrate Peptide
  • Receptors, Notch
  • sv protein, Drosophila
  • DNA
  • Egfr protein, Drosophila
  • ErbB Receptors