Extended Data Fig. 1: Ultrastructure of the basement membrane along the migratory route of the primordium and the characterization of the TgBAC(lamC1:lamC1-sfGFP) line.
From: Rear traction forces drive adherent tissue migration in vivo
a, Overview of the primordium. Dotted lines indicate the location of the cross-sections shown in (b-e). b-e, TEM images of cross-sections at the level of the most recently deposited neuromast (b), at the level of the primordium’s rear (c), at the level of the primordium’s front (d), and in front of the primordium (e). Scale bars = 10 μm. b’-e’, Magnification of area outlined by a dotted line in (b-e). Scale bars = 1 μm. The skin (s), primordium (p, purple hue), the muscle (m), and the BM (arrows) are indicated. n = 1 embryo. f, Schematic of the TgBAC(lamC1:lamC1-sfGFP) transgene. g, Image of the expression of LamC1-sfGFP from TgBAC(lamC1:lamC1-sfGFP) transgene in a 28 hpf embryo. The image is a sum-projected z-stack. Scale bar = 0.5 mm. h, The TgBAC(lamC1:lamC1-sfGFP) transgene partly rescues the lamC1 mutant phenotype. Crosses from lamC1-/+; lamC1:lamC1-sfGFP to lamC1-/+ fish resulted in embryos with three different phenotypes shown on the left. Quantification of the phenotypic categories from these crosses for non-transgenic embryos and embryos expressing LamC1-sfGFP are shown on the right. Note that the mild phenotype correlates with the presence of LamC1-sfGFP and the severe phenotype represents the lamC1 mutant phenotype. Scale bars = 0.5 mm. i, Quantification of the primordium migration in the presence of different copy numbers of the TgBAC(lamC1:lamC1-sfGFP) transgene. Data points, means, and SD are indicated. n.s.: p = 0.6514 (non-transgenic vs. lamC1:lamC1-sfGFP/+), p = 0.7842 (non-transgenic vs. lamC1:lamC1-sfGFP/lamC1:lamC1-sfGFP) (two-tailed Mann-Whitney test). j, Cross-section along apical-basal axis of a primordium (dotted line in top panel) of embryos expressing LamC1-sfGFP (BM) and the Cdh1-tdTomato (skin). The LamC1-sfGFP signal is enhanced to saturated levels (bottom panel). Scale bars = 25 μm. k, Images of slices from a z-stack of 32 hpf TgBAC(cxcr4b:EGFP-CaaX) embryos stained for Fibronectin and GFP. Orthogonal views are shown. l, Images of slices from a z-stack of 32 hpf TgBAC(cxcr4b:EGFP-CaaX) embryos stained for Chondroitin sulfate and GFP. Orthogonal views are shown. For h, i, n= number of embryos.
