Compartments and organising boundaries in the Drosophila eye: the role of the homeodomain Iroquois proteins

• DOI: 10.1242/dev.126.22.4933
• Publication Date: 2021-04-26T03:53:52Z
• Authors: Florencia Cavodeassi; Ruth Diez del Corral; Sonsoles Campuzano; María Domínguez
• Keywords: Homeodomain Proteins; 0301 basic medicine; Receptors, Notch; Organizers, Embryonic; Gene Expression; Membrane Proteins; Nuclear Proteins; Wnt1 Protein; N-Acetylglucosaminyltransferases; Phosphoproteins; 03 medical and health sciences; Proto-Oncogene Proteins; Animals; Drosophila Proteins; Insect Proteins; Drosophila; Hedgehog Proteins; Photoreceptor Cells, Invertebrate; Tissue Distribution; Transcription Factors

Abstract The Drosophila eye is patterned by a dorsal-ventral organising centre mechanistically similar to those in the fly wing and the vertebrate limb bud. Here we show how this organising centre in the eye is initiated – the first event in retinal patterning. Early in development the eye primordium is divided into dorsal and ventral compartments. The dorsally expressed homeodomain Iroquois genes are true selector genes for the dorsal compartment; their expression is regulated by Hedgehog and Wingless. The organising centre is then induced at the interface between the Iroquois-expressing and non- expressing cells at the eye midline. It was previously thought that the eye develops by a mechanism distinct from that operating in other imaginal discs, but our work establishes the importance of lineage compartments in the eye and thus supports their global role as fundamental units of patterning.