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Fig. 2
asb2b mutant cardiomyocytes exhibit structural defects.
(a) Three-dimensional images of 50 hpf Tg(myl7:LIFEACT-GFP) WT and asb2b mutant hearts reveal differences in myofilament thickness and organization. Magnified views of myofilaments in white boxes are shown on the right. Myofilament thickness was measured in 50 hpf WT and asb2b mutant hearts (n=29 myofilaments from 5 hearts). (b) Three-dimensional images of 50 hpf Tg(myl7:LIFEACT-GFP);Tg(myl7:MKATE-CAAX) WT and asb2b mutant atria. The myofilaments in WT are organized across cell borders (arrows), whereas asb2b mutant hearts show disorganized myofilaments between adjacent cardiomyocytes (arrows). (c) Three-dimensional images of 50 hpf Tg(myl7:actn3b-EGFP) WT and asb2b mutant atria. Atrial cardiomyocytes in WT exhibit an organized z-band pattern across cell–cell borders (arrows), whereas those in asb2b mutants exhibit a disorganized z-band pattern (arrows). (d) Three-dimensional images of 50 hpf Tg(myl7:ras-GFP) WT and asb2b mutant hearts. Magnified views of myofilaments in white dotted boxes are shown on the right. Cardiomyocytes are outlined to define shape. (e) Single-plane images of 50 hpf Tg(myl7:EGFP-Podocalyxin);Tg(myl7:MKATE-CAAX) WT and asb2b mutant atria. In WT, EGFP-Podocalyxin is localized on the abluminal (apical) side of cardiomyocytes, whereas in asb2b mutants, it appears to be localized on both the abluminal and luminal (basal) sides (arrows). Number of cardiomyocytes exhibiting EGFP-Podocalyxin localization on the basal side in WT and asb2b mutant hearts (n=5 hearts, with averages taken from 20 cells per heart). *P<0.05 and **P<0.01 by one-way analysis of variance (ANOVA) followed by Tukey’s honest significant difference test. Error bars, s.e.m. Scale bars, 20 μm. At, atrium; V, ventricle.