The Drosophila LIM-homeo domain protein Islet antagonizes pro-neural cell specification in the peripheral nervous system.
The pattern of the external sensory organs (SO) in Drosophila depends on the activity of the basic helix-loop-helix (bHLH) transcriptional activators Achaete/Scute (Ac/Sc) that are expressed in clusters of cells (pro-neural clusters) and provide the cells with the potential to develop a neural fate. In the mesothorax, the GATA1 transcription ... factor Pannier (Pnr), together with its cofactor Chip, activates ac/sc genes directly through binding to the dorso-central enhancer (DC) of ac/sc. We identify the LIM-homeo domain (LIM-HD) transcription factor Islet (Isl) by genetic screening and investigate its role in the thoracic pre-patterning. We show that isl loss-of-function mutations result in expanded Ac expression in DC and scutellar (SC) pro-neural clusters and formation of ectopic sensory organs. Overexpression of Isl decreases pro-neural expression and suppresses bristle development. Moreover, Isl is coexpressed with Pnr in the posterior region of the mesothorax. In the DC pro-neural cluster, Isl antagonizes Pnr activity both by dimerization with the DNA-binding domain of Pnr and via competitive inhibition of the Chip-bHLH interaction. We propose that sensory organ pre-patterning relies on the antagonistic activity of individual Chip-binding factors. The differential affinities of these binding-factors and their precise stoichiometry are crucial in specifying pre-patterns within the different pro-neural clusters.
Mesh Terms:
Animals, Body Patterning, Cell Differentiation, Dimerization, Drosophila, Drosophila Proteins, Homeodomain Proteins, Larva, Mutation, Nervous System, Neurons, Nuclear Proteins, Protein Binding, Pupa, Sense Organs, Stem Cells, Transcription Factors
Animals, Body Patterning, Cell Differentiation, Dimerization, Drosophila, Drosophila Proteins, Homeodomain Proteins, Larva, Mutation, Nervous System, Neurons, Nuclear Proteins, Protein Binding, Pupa, Sense Organs, Stem Cells, Transcription Factors
Dev. Biol.
Date: Dec. 15, 2005
PubMed ID: 16259974
View in: Pubmed Google Scholar
Download Curated Data For This Publication
201168
Switch View:
- Interactions 4