Signaling in the third dimension: The peripodial epithelium in eye disc development

Abstract

The eye-antennal imaginal disc of Drosophila melanogaster has often been described as an epithelial monolayer with complex signaling events playing out in two dimensions. However, the imaginal disc actually comprises two opposing epithelia (the peripodial epithelium, or PE, and the disc proper, or DP) separated by a lumen to form a sac-like structure. Recent studies expose complex molecular interactions between the PE and the DP, and reveal dynamic communication between the two tissues. Further findings suggest the PE makes important contributions to DP development by acting as a source of signaling molecules as well as cells. Here we summarize those findings and highlight implications for further research.

The eye imaginal disc as a model to study the coordination of neuronal and glial development

“…Glial cells, however, have been frequently ignored and the use of the developing eye as a beautiful case to study the coordination of neuronal and glial differentiation has been neglected. In the following, we will briefly recapitulate the development of the Drosophila eye, which has been reviewed extensively elsewhere 5,6,10,11 and glial development and then focus on how the communication between the two cell types is orchestrated.…”

Dorsal eye selector pannier (pnr) suppresses the eye fate to define dorsal margin of the Drosophila eye

“…The imaginal disc is a sac-like structure present inside the larva, which is the product of two different layers: the p eripodial m embrane ( PM ) and the d isc p roper ( DP ). The Drosophila retina develops from the DP while the PM of the eye-antennal imaginal disc contributes to the adult head structures (Milner et al, 1983; Haynie and Bryant, 1986; Atkins and Mardon, 2009). Morphogenesis during animal development involves signaling between different layers of the tissue (Furuta and Hogan, 1998; Obara-Ishihara et al, 1999).…”

“…Morphogenesis during animal development involves signaling between different layers of the tissue (Furuta and Hogan, 1998; Obara-Ishihara et al, 1999). Similarly, signaling between the PM and the DP of the eye disc is essential for D orso -v entral (DV) axis establishment and patterning (Cho et al, 2000; Gibson and Schubiger, 2000; Atkins and Mardon, 2009). …”

Developmentally regulated autophagy is required for eye formation in Drosophila

“…Some eye selector genes including ey (eyeless), Optix and eya (eyes absent) are expressed in the peripodial membrane, yet with unknown function [57], and ey-Gal4(II) is also active in this part of the eye disc [42]. To examine the possible contribution of autophagy in the peripodial membrane to eye development, we inactivated Atg genes exclusively in this tissue by using c311-Gal4 driver [42], and found no alteration in the eye structure of animals tested (Table S2 and Fig.…”