Fig. 6
Tissue-scale planar polarisation of actomyosin. a–p Top-down 1-μm Z-projection of the linear heart tube at 30 hpf stained for Alcam (a, e, i, m) to visualise ventricular membranes, (Tg(myl7:LifeAct-GFP, counter-stained with anti-GFP) (b, j, n) or Phalloidin (f) to visualise F-actin (green in d, h, l, p), and pMRLC (c, g, k, o, magenta in d, h, l, p). The proximal ventricular region is labelled with a white asterisk, the distal ventricular region with a yellow asterisk, (a–c, e–g, i–k, m–o). In control hearts both F-actin (b, green in d) and pMRLC (c, magenta in d) are tissue-scaled planar-polarised in the myocardial epithelium, with higher levels in the distal ventricular region (yellow asterisk) and the OFT than in the proximal ventricular region (white asterisk) and near the AV (8/10 hearts with planar-polarised actomyosin, N = 2). In 30 hpf linear heart tubes of double wnt5bta98;wnt11tx226 mutants (e–h, 0/8 hearts with planar-polarised actomyosin, N = 2), fzd7ae3 mutants (i–l, 1/9 hearts with planar-polarised actomyosin, N = 2), and vangl2m209 mutants (m–p, 3/15 hearts with planar-polarised actomyosin, N = 2), both F-actin (f, j, n, green in h, l, p) as well as pMRLC (g, k, o, magenta in h, l, p) are localised throughout the ventricle. Hearts were counter-stained for DAPI to label nuclei (blue in d, h, l, p). Scale bars, 10 μm. AV, atrio-ventricular junction
