Dynamic cell shapes and contacts in the developing Drosophila retina are regulated by the Ig cell adhesion protein hibris

Abstract

Cell shapes and contacts are dynamically regulated during organogenesis to enable contacts with relevant neighboring cells at appropriate times. During Drosophila larval eye development, an apical contact is established between one pair of non-neuronal cones cells, precluding contact between the opposing pair. Concurrent with changes in cell shape, these contacts reverse in early pupal life. The reversal in cone cell contacts occurs in a posterior to anterior gradient across the eye, following the developmental gradient established in the larval eye imaginal disc. Hibris (Hbs), an Immunoglobulin cell adhesion molecule homologous to vertebrate Nephrin, is required for cone cell morphogenesis. In hbs null mutants, a majority of cone cells fail to both establish wild-type contacts and achieve mature cone cell shapes. hbs acts cell autonomously in the cone cells to drive these changes. The work presented here indicates hbs contributes to the remodeling of cell contacts and cell shapes throughout development. Developmental Dynamics 238: 2223-2234, 2009.

The lens in focus: a comparison of lens development in Drosophila and vertebrates

“…After PPC recruitment, the apical surfaces of the eq/pl CCs begin to migrate over the top of the a/p CCs and meet in the middle, forcing a/p CC separation. Like the a/p CCs earlier, the eq/ pl CC junctions also expand downward through integrin receptor-mediated contacts, further separating the PRs into four groups—R1/8, R 2/3, R4/5, and R6/7 (Wolff and Ready 1993; Longley and Ready 1995; Grillo-Hill and Wolff 2009). Integrin receptors are comprised of a β-subunit complexed with either an α-ps1 or ps2 subunit, and are required for retinal floor integrity (Wilcox et al 1984; Bogaert et al 1987; Leptin et al 1987; Longley and Ready 1995).…”

“…In contrast to CC–CC interactions, CC–PPC and PPC–IOC contacts require E-cadherin homophilic interactions, Rst-Hbs heterophilic interactions, and the ZO-1-related apical protein Polychaetoid (Bao and Cagan 2005; Seppa et al 2008; Grillo-Hill and Wolff 2009). Hbs and Rst are also highly integrated with cell signaling pathways to allow proper patterning and cell number restriction (see Bao 2010 for review).…”

Cell Adhesion in the Assembly of theDrosophilaEye

“…Normally, anterior-posterior cone cells are separated by equatorial-posterior cone cells ( Figure 1A-B). In hbs mutants, anterior-posterior cone cells retain their contacts at a stage when they are separate in a normal ommatidium (Grillo-Hill & Wolff, 2009). Sns, another IRM adhesion molecule of the Nephrin group, is also found in cone cells and PPCs in a manner similar to Hbs .…”

Neph/Nephrin-like adhesion and tissue level pulling forces regulate cell intercalation during Drosophila retina development

“…The PPCs express the Nephrin-like immunoglobulin adhesion protein Hibris (Hbs) that is thought to bind the homologue of Neph-1, Roughest (Rst), which is expressed in the IOCs (Bao and Cagan, 2005). Furthermore, Hbs regulates CC intercalation (Grillo-Hill and Wolff, 2009).…”