Bilateral cellular flows display asymmetry prior to left-right organizer formation in amniote gastrulation

• 成果类型: Article
• 署名作者: Asai, Rieko; Sinha, Shubham; Prakash, Vivek N.; Mikawa, Takashi
• 署名单位: University of California System; University of California San Francisco; Kumamoto University; University of Miami; University of Miami; University of Miami
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-14334
• DOI: 10.1073/pnas.2414860122
• 发表日期: 2025-02-03
• 关键词: chick primitive streak; molecular-models; gene-expression; hensens node; embryo; intercalation; movements; chirality; patterns; cilia

摘要

A bilateral body plan is predominant throughout the animal kingdom. Bilaterality of amniote embryos becomes recognizable as midline morphogenesis begins at gastrulation, bisecting an embryonic field into the left and right sides, and left-right (LR) asymmetry patterning follows. While a series of laterality genes expressed after the LR compartmentalization has been extensively studied, the laterality patterning prior to and at the initiation of midline morphogenesis has remained unclear. Here, through a biophysical quantification in a high spatial and temporal resolution, applied to a chick model system, we show that a large- scale bilateral counterrotating cellular flow, termed polonaise movements, display LR asymmetries in early gastrulation. This cell movement starts prior to the formation of the primitive streak (PS) (the earliest midline structure) and the subsequent appearance of Hensen's node (the LR organizer). The cellular flow speed and vorticity unravel the location and timing of the LR asymmetries. The bilateral flows displayed a Right dominance after 6 h since the start of cell movements. Mitotic arrest that diminishes PS formation resulted in changes in the bilateral flow pattern, but the Right dominance persisted. Our data indicate that the LR asymmetry in amniote gastrula becomes detectable earlier than suggested by current models, which assume that the asymmetric regulation of the laterality signals during embryonic development.