|
Display additional annotations [+]
Gene |
Clone |
Species |
Stages |
Anatomy |
fn1
|
|
laevis
|
NF stage 15
to
NF stage 28
|
ectoderm
,
mesoderm
,
endoderm
,
primary heart field
|
tpm1
|
|
laevis
|
NF stage 28
to
NF stage 32
|
endocardial tube
,
cardiac myocyte
|
ctnnb1
|
|
laevis
|
NF stage 15
to
NF stage 28
|
ectoderm
,
mesoderm
,
cardiac myocyte
|
tjp1
|
|
laevis
|
NF stage 15
to
NF stage 32
|
ectoderm
,
mesoderm
,
endoderm
,
endocardial tube
|
fbn1
|
|
laevis
|
NF stage 15
to
NF stage 28
|
extracellular matrix
,
primary heart field
|
|
|
Figure 1. (A) Xenopus embryos at three stages during HPC (red) movement to the ventral midline. hpf, hours post-fertilization.
(B) Transverse schematic of HPCs and their microenvironment (blue, ectoderm; red, mesoderm; yellow, endoderm; brown, fibronectin; purple, fibrillin; orange, aPKC; green, ZO-1; dark red, tropomyosin).
(C) Cell shapes by β-catenin localization and cardiomyocytes by tropomyosin expression. Note: red spot (asterisk) in stage 28 is non-specific staining outside the embryo.
(D) aPKC appears on the apical surface of HPCs (white arrows) with fibrillin at the HPC basal surface.
(E) Tight junction protein ZO-1 appears perinuclearly and nascently on the apical surface by stage 23 and strongly at HPC apical intercellular junctions by stage 28. Fibronectin appears at all germ-layer interfaces.
(F–I) Apical aPKC (F and G) and ZO-1 (H and I) during early heart-tube formation. Immunofluorescence shows epithelial individual markers and tropomyosin (F and H, upper panels) and normalized intensity with pseudocolor lookup table (LUT) (F and H, lower panels).
(G and I) Quantification of apical polarity from five or six embryos per time point over two clutches.
Scale bars, 50 μm. ∗p < 0.05, ∗∗p < 0.01. See also Figure S1. |
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Display additional annotations [+]
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Figure 2. (A–C) Modulators of tissue compliance applied during stages of early heart development exhibit defects, including pericardial and neural edemas (A) (see arrows; scale bar, 1 mm), altered AP length (B), and increased rates of edema per clutch (C) (n = 30–35 embryos over four clutches).
(D) Compliance measured by microaspiration of HFR.
(E) Compliance at stage 22 confirms that blebbistatin and Y27632 increase and calyculin A decreases compliance (n = 11–17 embryos per treatment over three clutches).
(F) Transverse sections through HFR at stage 28 show changes in polarity (aPKC or ZO-1) within the progenitor population (red). Lower panels show the epithelial marker masked using tropomyosin expression (scale bar, 50 μm).
(G) Apical intensity after small-molecule inhibitor treatment (n = 9–13 embryos over four clutches).
(H) Representative lateral confocal sections of stage 39 tadpole hearts (scale bar, 100 μm).
(I) Cardiac anatomy after stage-specific inhibitor treatments as shown in Figure S2 (n = 5 embryos per treatment per period).
Error bars represent mean ± SEM. ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001. See also Figures S1, S2, and S3A. |