The same but different: cell intercalation as a driver of tissue deformation and fluidity

Abstract

The ability of cells to exchange neighbours, termed intercalation, is a key feature of epithelial tissues. Intercalation is predominantly associated with tissue deformations that drive morphogenesis. More recently, however, intercalation that is not associated with large-scale tissue deformations has been described both during animal development and in mature epithelial tissues. This latter form of intercalation appears to contribute to an emerging phenomenon that we refer to as tissue fluidity—the ability of cells to exchange neighbours without changing the overall dimensions of the tissue. Here, we discuss the contribution of junctional dynamics to intercalation governing both morphogenesis and tissue fluidity. In particular, we focus on the relative roles of junctional contractility and cell–cell adhesion as the driving forces behind intercalation. These two contributors to junctional mechanics can be used to simulate cellular intercalation in mechanical computational models, to test how junctional cell behaviours might regulate tissue fluidity and contribute to the maintenance of tissue integrity and the onset of disease. This article is part of the Theo Murphy meeting issue ‘Mechanics of development’.

TheDrosophilaAfadin and ZO-1 homologues Canoe and Polychaetoid act in parallel to maintain epithelial integrity when challenged by adherens junction remodeling

“…Recent work has suggested that tissues can undergo “solid-to-liquid” transitions, allowing cell rearrangements and thus driving morphogenetic events such as Drosophila germband elongation (e.g., Tetley and Mao, 2018; Yan and Bi, 2019). This event involves modulation of both cytoskeletal contractility and cell adhesion.…”

Fog signaling has diverse roles in epithelial morphogenesis in insects

“…Such intercalation events could be triggered by local tension in the epithelium as described in other systems (e.g. Aigouy et al, 2010) and could thereby serve to maintain tissue fluidity and reduce anisotropy in tissue tension (Tetley and Mao, 2018; Tetley et al, 2019). A recent preprint examines this process in further detail (Jain et al, 2019).…”

The asynchronous growth and movement reconstruction of the early molting animals

“…As segments annelids can form from single-cell-wide precursors [9], daughter cells emerge during elongation process of the ring ( Figure S1e-g). The rosette pattern being treat as an inter phase of the elongation process [41]. The boundary cells constraint the cell ow within each ring which may explain the rosette pattern formed near the boundary of the ring.…”