Elsevier

Mechanisms of Development

Volume 141, August 2016, Pages 25-31
Mechanisms of Development

Spalt-mediated dve repression is a critical regulatory motif and coordinates with Iroquois complex in Drosophila vein formation

https://doi.org/10.1016/j.mod.2016.06.004Get rights and content
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Highlights

  • Low-level Dve activity is required for vein formation during a critical period.

  • Spalt-mediated dve repression at prepupal stage is crucial for vein formation.

  • The coordinated action between Dve and Iroquois complex is involved in the L5 vein formation.

Abstract

Veins are longitudinal cuticular structures that maintain shape of the wing. Drosophila melanogaster has six longitudinal veins (L1–L6) and two cross veins. The Zn-finger transcription factors of Spalt-complex (Sal) are required for positioning of the L2 and L5, and the homeodomain transcription factors of Iroquois complex (Iro-C) are required for formation of the L3 and L5 veins.

The homeodomain transcriptional repressor Defective proventriculus (Dve) is uniformly expressed in the wing pouch of the larval imaginal disc. However, dve mutant wings showed loss of the L2 and L5, but not of the L3 and L4 veins. Temporal dve knockdown experiments indicate that the Dve activity is required for vein formation from late third larval instar to the prepupal stage. In the prepupal wing, Dve expression becomes nearly complementary to that of Sal through the Sal-mediated dve repression. Furthermore, coexpression of Dve and Iro-C relieved of Sal-mediated repression is required for the L5 formation in a dose-dependent manner. The relationship between Sal, Dve, and Iro-C in wing vein specification is quite similar to that in ommatidial cell-type specification. Our results provide information about the conserved function of dve regulatory motifs in cell differentiation.

Keywords

Drosophila
Wing vein
Transcription factor
Iroquois
Spalt
Dpp

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1

Present address: Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Japan.