Identification of hunchback cis-regulatory DNA conferring temporal expression in neuroblasts and neurons

Gene Expr Patterns. Jan-Feb 2012;12(1-2):11-7. doi: 10.1016/j.gep.2011.10.001. Epub 2011 Oct 20.

Abstract

The specification of temporal identity within single progenitor lineages is essential to generate functional neuronal diversity in Drosophila and mammals. In Drosophila, four transcription factors are sequentially expressed in neural progenitors (neuroblasts) and each regulates the temporal identity of the progeny produced during its expression window. The first temporal identity is established by the Ikaros-family zinc finger transcription factor Hunchback (Hb). Hb is detected in young (newly-formed) neuroblasts for about an hour and is maintained in the early-born neurons produced during this interval. Hb is necessary and sufficient to specify early-born neuronal or glial identity in multiple neuroblast lineages. The timing of hb expression in neuroblasts is regulated at the transcriptional level. Here we identify cis-regulatory elements that confer proper hb expression in "young" neuroblasts and early-born neurons. We show that the neuroblast element contains clusters of predicted binding sites for the Seven-up transcription factor, which is known to limit hb neuroblast expression. We identify highly conserved sequences in the neuronal element that are good candidates for maintaining Hb transcription in neurons. Our results provide the necessary foundation for identifying trans-acting factors that establish the Hb early temporal expression domain.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Genetically Modified / genetics
  • Animals, Genetically Modified / growth & development
  • Animals, Genetically Modified / metabolism
  • Base Sequence
  • Binding Sites
  • Central Nervous System / cytology
  • Central Nervous System / growth & development
  • Central Nervous System / metabolism
  • Chromosomes, Insect / genetics
  • Chromosomes, Insect / metabolism
  • DNA-Binding Proteins / genetics*
  • DNA-Binding Proteins / metabolism
  • Drosophila / genetics*
  • Drosophila / growth & development
  • Drosophila / metabolism
  • Drosophila Proteins / genetics*
  • Drosophila Proteins / metabolism
  • Gene Expression Regulation, Developmental*
  • Genes, Reporter
  • Mammals / genetics
  • Mammals / metabolism
  • Molecular Sequence Data
  • Neurons / cytology*
  • Neurons / metabolism
  • Regulatory Elements, Transcriptional*
  • Time Factors
  • Trans-Activators / genetics
  • Trans-Activators / metabolism
  • Transcription Factors / genetics*
  • Transcription Factors / metabolism
  • Transgenes

Substances

  • DNA-Binding Proteins
  • Drosophila Proteins
  • Trans-Activators
  • Transcription Factors
  • hb protein, Drosophila