Cell Flow Reorients the Axis of Planar Polarity in the Wing Epithelium of Drosophila

Abstract

Planar cell polarity (PCP) proteins form polarized cortical domains that govern polarity of external structures such as hairs and cilia in both vertebrate and invertebrate epithelia. The mechanisms that globally orient planar polarity are not understood, and are investigated here in the Drosophila wing using a combination of experiment and theory. Planar polarity arises during growth and PCP domains are initially oriented toward the well-characterized organizer regions that control growth and patterning. At pupal stages, the wing hinge contracts, subjecting wing-blade epithelial cells to anisotropic tension in the proximal-distal axis. This results in precise patterns of oriented cell elongation, cell rearrangement and cell division that elongate the blade proximo-distally and realign planar polarity with the proximal-distal axis. Mutation of the atypical Cadherin Dachsous perturbs the global polarity pattern by altering epithelial dynamics. This mechanism utilizes the cellular movements that sculpt tissues to align planar polarity with tissue shape.

The physics of life

“…Others are using ideas from active matter to 13 . Some biologists hope that such studies will reveal the fundamental principles that govern how cells divide, take shape or move.…”

Regulation of leg size and shape: Involvement of the Dachsous‐fat signaling pathway

“…Since the Dpp gradient in the wing disc may provide PVs, positional information may be linked to cell proliferation via the activity of the Ds-Ft signaling pathway. Furthermore, since Ft and Ds influence planar cell polarity (PCP), the vector of their expression gradients may determine PCP along the PD axis (Casal et al, 2006;Aigouy et al, 2010;Harumoto et al, 2010).…”

Caresser la polarité planaire dans le sens du flot

“…Nous avons d'abord considéré le cas  = 0, pour lequel la réorientation de la polarité dépend uniquement des rotations locales et non du cisaillement pur. Dans ce cas, l'axe de polarité planaire pivote vers l'axe PD mais cette réo-rientation est incomplète [7]. Ce résultat indique que les rotations locales, à elles seules, ne suffisent pas à expliquer la réorientation observée expérimentale-ment et que le cisaillement pur doit lui aussi jouer un rôle (c'est-à-dire :   0).…”

“…tissu ( Figure 1D) [7,8]. Au cours du temps et jusqu'à 32 heures AFP, cet axe de polarité pivote et s'aligne sur l'axe PD [7] ( Figure 1E).…”

“…Au cours du temps et jusqu'à 32 heures AFP, cet axe de polarité pivote et s'aligne sur l'axe PD [7] ( Figure 1E). En conclusion, la polarité planaire ne se développe pas de novo, mais elle se réoriente au cours du développement.…”