Fig. 3
Epithelial and mesenchymal cell rearrangements converge and extend the midportion of the mandibular arch. a Orientation of epithelial tetrads during T1 transitions at formation to resolution stages (separated by an arrow); n = 3 embryos at 21 somite stage. b Schematic representation of predominant orientation of epithelial T1 transitions in middle and distal regions. c Time series (taken from 120 min. time lapse moves) of volumes of mesenchymal cells of dual H2B-GFP;mTmG transgenic embryos visualised by light sheet microscopy at intermediate and high magnification. Select nuclei are coloured to show tissue and cell convergence at intermediate and small scales occurs in the middle, but not distal, region. (Representative of 5 embryos at 19–21 somite stage). d Schematic representation of oriented mesenchymal cell intercalations transverse to the axis of elongation in the middle region. e In the mid-portion of the arch, F-actin and phosphomyosin light chain (pMLC) were biased along proximal and distal epithelial and mesenchymal cell interfaces which is parallel to the rostrocaudal axis and to the direction of cell intercalations. The angular distribution of immunostain fluorescence intensity for epithelial (n = 4 embryos) and mesenchymal (n = 4 embryos) F-actin and epithelial phosphomyosin light chain (pMLC) (n = 5 embryos) relative to the arch long axis that was designated as 0o was quantified in the middle region using SIESTA. Scale bar: 20 μm, asterisks denote p < 0.05, Student’s t-test, error bars denote s.e.m. Source data are provided as a Source Data file
