Polychaetoid controls patterning by modulating adhesion in the Drosophila pupal retina

Abstract

Correct cellular patterning is central to tissue morphogenesis, but the role of epithelial junctions in this process is not well-understood. The Drosophila pupal eye provides a sensitive and accessible model for testing the role of junction-associated proteins in cells that undergo dynamic and coordinated movements during development. Mutations in polychaetoid (pyd), the Drosophila homologue of Zonula Occludens-1, are characterized by two phenotypes visible in the adult fly: increased sensory bristle number and the formation of a rough eye produced by poorly arranged ommatidia. We found that Pyd was localized to the adherens junction in cells of the developing pupal retina. Reducing Pyd function in the pupal eye resulted in mis-patterning of the interommatidial cells and a failure to consistently switch cone cell contacts from an anterior-posterior to an equatorial-polar orientation. Levels of Roughest, DE-Cadherin and several other adherens junction-associated proteins were increased at the membrane when Pyd protein was reduced. Further, both over-expression and mutations in several junction-associated proteins greatly enhanced the patterning defects caused by reduction of Pyd. Our results suggest that Pyd modulates adherens junction strength and Roughest-mediated preferential cell adhesion.

The Drosophila L1CAM homolog Neuroglian signals through distinct pathways to control different aspects of mushroom body axon development

“…Our observation that NRG and PYD interact to mediate proper sister neurite projections defines a novel role for the ZO-1 homolog PYD in axonogenesis. Thus far, the best-known role of MAGUKs in the nervous system has been in synapse development and function, as is the case for one of the prototypic MAGUKs, Drosophila Discs Large 1 (Dlg1) (Tejedor et al, 1997;Thomas et al, 1997), whereas PYD is known as a component of adherens junctions (Jung et al, 2006;Seppa et al, 2008).…”

Mutational analysis supports a core role forDrosophilaα-Catenin in adherens junction function

“…In Drosophila, a-Catenin function has been assessed through RNA interference (RNAi), which does not fully deplete aCatenin (Magie et al, 2002;Cavey et al, 2008;Seppa et al, 2008). These experiments showed that Drosophila a-Catenin is required for AJ function and integrity.…”

The LH/CG receptor activates canonical signaling pathway when expressed in Drosophila

“…Third instar eye of gmr-Gal4 crosses were dissected and the histology was performed as previously described (Seppa et al, 2008). Expression was detected by confocal (Zeiss) using anti-HA (Roche, 1:200; 2 antibody anti-rat568 (1:250)) or antiserum raised against the CGb subunit (1:1500; 2 antibody ant-rabbit 488 (1:250)).…”