The Notochord Breaks Bilateral Symmetry by Controlling Cell Shapes in the Zebrafish Laterality Organ

Abstract

Kupffer's vesicle (KV) is the zebrafish organ of laterality, patterning the embryo along its left-right (LR) axis. Regional differences in cell shape within the lumen-lining KV epithelium are essential for its LR patterning function. However, the processes by which KV cells acquire their characteristic shapes are largely unknown. Here, we show that the notochord induces regional differences in cell shape within KV by triggering extracellular matrix (ECM) accumulation adjacent to anterior-dorsal (AD) regions of KV. This localized ECM deposition restricts apical expansion of lumen-lining epithelial cells in AD regions of KV during lumen growth. Our study provides mechanistic insight into the processes by which KV translates global embryonic patterning into regional cell shape differences required for its LR symmetry-breaking function.

Evolution and Expression of Paxillin Genes in Teleost Fish

“…pxna expression was enriched in developing somites and posterior notochord at 14 hpf (Fig 6B, 6C, 6G and 6H). Additionally, expression of pxna was observed in Kupffer’s vesicle (Fig 6B), a ciliated epithelial organ that orients the left-right body axis [28–30] During these stages of development, an ECM rich in Fibronectin and Laminin is generated around the notochord, somites, and Kupffer’s vesicle [31–33]. Previous antibody labeling has suggested that zebrafish Paxillin proteins may be crucial for adhesion and morphogenesis of these tissues at this stage [18].…”

Concerted action of neuroepithelial basal shrinkage and active epithelial migration ensures efficient optic cup morphogenesis

“…Wild type strains (WT-AB RRID:ZIRC_ZL1, WT-TL RRID:ZIRC_ZL86) and transgenic lines Tg(actb1:GFP-utrCH), (Behrndt et al, 2012), Tg(actb2:mCherry-Hsa.UTRN) (Compagnon et al, 2014), Tg(actb1:myl12.1-EGFP) (Maître et al, 2012), Tg(actb1:HRAS-EGFP) vu119 (Cooper et al, 2005), Tg( vsx2 ::GFP) (Kimura et al, 2006), Tg(βactin:mKate2-ras) were used. Zebrafish were maintained and bred at 26.5°C.…”

Mathematical modelling of fluid transport and its regulation at multiple scales

“…The left-right axis of the embryo is established by fluid-cell interactions inside a tissue cyst, called Kupffer's vesicle (Compagnon et al, 2014;Oteíza et al, 2008). The lumen diameter grows up to 50 mm within about 100 min and it remains to be determined how such rapid growth is achieved and which solutes are responsible.…”