Epithelial bending is a fundamental process that shapes organs during development. All currently known mechanisms involve cells locally changing shape from columnar to wedge-shaped. Often this shape change occurs by cytoskeletal contraction at cell apices (“apical constriction”) but mechanisms such as basal nuclear positioning (“basal wedging”) or extrinsic compression are also known. Here we demonstrate a completely different mechanism which occurs without cell wedging. In mammalian salivary glands and teeth, we show that initial invagination occurs through coordinated vertical cell movement. Specifically, we show that cells towards the periphery of the placode move vertically upwards while their more central neighbours move downwards to create the invagination. We further show that this occurs by active cell-on-cell migration: outer cells migrate with an apical leading edge protrusion, depressing the central cells to “telescope” the epithelium downwards into the underlaying mesenchyme. Cells remain basally attached to the underlying lamina while their apical protrusions are dynamic and planar polarised centripetally. These protrusions depend on the actin cytoskeleton, and inhibition of the branching molecule Arp2/3 inhibits them and the invagination. FGF and Hedgehog morphogen signals are also required, with FGF providing a directional cue. These findings show that epithelial bending can be achieved by novel morphogenetic mechanism of coordinated cell rearrangement quite distinct from previously recognised invagination processes.
- Downloaded 519 times
- Download rankings, all-time:
- Site-wide: 63,849
- In developmental biology: 1,540
- Year to date:
- Site-wide: 144,952
- Since beginning of last month:
- Site-wide: 127,128
Downloads over time
Distribution of downloads per paper, site-wide
- 27 Nov 2020: The website and API now include results pulled from medRxiv as well as bioRxiv.
- 18 Dec 2019: We're pleased to announce PanLingua, a new tool that enables you to search for machine-translated bioRxiv preprints using more than 100 different languages.
- 21 May 2019: PLOS Biology has published a community page about Rxivist.org and its design.
- 10 May 2019: The paper analyzing the Rxivist dataset has been published at eLife.
- 1 Mar 2019: We now have summary statistics about bioRxiv downloads and submissions.
- 8 Feb 2019: Data from Altmetric is now available on the Rxivist details page for every preprint. Look for the "donut" under the download metrics.
- 30 Jan 2019: preLights has featured the Rxivist preprint and written about our findings.
- 22 Jan 2019: Nature just published an article about Rxivist and our data.
- 13 Jan 2019: The Rxivist preprint is live!