XB-IMG-151645
Xenbase Image ID: 151645
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Fig. 3. Adprhl1 morpholino disrupts myofibril assembly in the forming ventricle. Comparison of dissected hearts from tadpoles injected with Adprhl1-e2i2MO (A, B, E, F) into d-2/4 blastomeres versus those containing control morpholino (C, D, G, H). Phalloidin stain of actin filaments (red) and immunocytochemistry for myosin heavy chain (green) is presented (+DAPI nuclei-blue-F, H). S. Fig. 6 contains additional data, including higher magnification images for stage 33, 37 and stage 40 ventricles. A-D: At the onset of cardiac looping, stage 33, left lateral view of heart tubes. (apex-white arrowheads). E-H: After outgrowth of the ventricle, stage 40 hearts (E, G) oriented with anterior surface upwards, showing myofibril patterns (arrowheads) in the ventricle wall (F, H). Scale bars = 100 μm (A, C, E, G). Scale bars = 10 μm (F, H). I: Cell number and size measurements for the hearts depicted here and S. Fig. 6. At stage 33, cardiac looping is more advanced in the control heart but cell surface area is comparable to the morphant. At stage 37 and 40, fewer cells are present on the surface of smaller morphant ventricles. J-N: Illustrations showing normal morphology and myofibril patterns in the forming ventricle. J: Wildtype stage 33 heart tube, depicting cardiomyocytes on the left side that elongate to form a rosette structure, an early cell movement observed during looping morphogenesis that is absent from morphants. K: A stage 40 heart ventricle, with contours (grey lines) to represent circumference-axes running from base to apex (from inner to outer curvature). Alignment of myofibrils is described relative to these axes. L-N: Simplified arrangement of myofibrils at three locations within the ventricle chamber. Myofibrils near the base (inner curvature-L) orient parallel to the axes. Conversely, around the apex, the predominant orientation of larger myofibrils extends perpendicular to the axes (M), at least for cardiomyocytes on the outer (apical) surface of the chamber. At deeper positions towards the lumen, myofibrils of trabecular (Tr) cardiomyocytes align parallel to the axes (N). There is no abrupt boundary between cardiomyocytes that contain perpendicular or parallel-oriented myofibrils. Moreover, the extent of the perpendicular cells is greater on the anterior ventricle wall (left sided origin) and lesser on the posterior wall (right origin). Image published in: Smith SJ et al. (2016) © 2016 The Authors. This image is reproduced with permission of the journal and the copyright holder. This is an open-access article distributed under the terms of the Creative Commons Attribution license
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