Transcriptional regulation of the Drosophila glial gene repo

Mech Dev. 2005 Jun;122(6):849-62. doi: 10.1016/j.mod.2005.01.002. Epub 2005 Mar 11.


reversed polarity (repo) is a putative target gene of glial cells missing (gcm), the primary regulator of glial cell fate in Drosophila. Transient expression of Gcm is followed by maintained expression of repo. Multiple Gcm binding sites are found in repo upstream DNA. However, while repo is expressed in Gcm positive glia, it is not expressed in Gcm positive hemocytes. These observations suggest factors in addition to Gcm are required for repo expression. Here we have undertaken an analysis of the cis-regulatory DNA elements of repo using lacZ reporter activity in transgenic embryos. We have found that a 4.2 kb DNA region upstream of the repo start site drives the wild-type repo expression pattern. We show that expression is dependent on multiple Gcm binding sites. By ectopically expressing Repo, we show that Repo can regulate its own enhancer. Finally, by systematically analyzing fragments of repo upstream DNA, we show that expression is dependent on multiple elements that are responsible for activity in subsets of glia, as well as repressing inappropriate expression in the epidermis. Our results suggest that Gcm acts synergistically with other factors to control repo transcription in glial cells.

Publication types

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

MeSH terms

  • Animals
  • Binding Sites
  • Cell Size
  • Central Nervous System / embryology
  • DNA / metabolism
  • DNA-Binding Proteins
  • Drosophila Proteins / biosynthesis*
  • Drosophila Proteins / genetics*
  • Drosophila melanogaster
  • Epidermis / metabolism
  • Gene Expression Regulation, Developmental*
  • Genes, Insect / genetics
  • Genes, Reporter
  • Hemocytes / metabolism
  • Homeodomain Proteins / biosynthesis*
  • Homeodomain Proteins / genetics*
  • Immunohistochemistry
  • Lac Operon
  • Models, Genetic
  • Mutation
  • Neuroglia / metabolism
  • Neuropeptides / metabolism
  • Phenotype
  • Promoter Regions, Genetic
  • Trans-Activators / metabolism
  • Transcription Factors
  • Transcription, Genetic
  • Transcriptional Activation


  • DNA-Binding Proteins
  • Drosophila Proteins
  • GCM protein, Drosophila
  • Homeodomain Proteins
  • Neuropeptides
  • Trans-Activators
  • Transcription Factors
  • repo protein, Drosophila
  • DNA