ZFIN is incorporating published figure images and captions as part of an ongoing project. Figures from some publications have not yet been curated, or are not available for display because of copyright restrictions.

ZFIN is incorporating published figure images and captions as part of an ongoing project. Figures from some publications have not yet been curated, or are not available for display because of copyright restrictions.

Effects of CDK9 inhibition or knockdown on the structure and function of the developing zebrafish heart. For pharmacological inhibition (A), embryos were continuously exposed to vehicle (1% DMSO, clear bars) or flavopiridol (3µmol/l, dark bars) from 24 to 120hpf. For morpholino-mediated knockdown (B), embryo eggs at the one- to two-cell stage were injected with Cdk9 mismatch morpholino (clear bars) or Cdk9-targeting morpholino (SB, black bars). Ventricle ejection fraction (A,B, upper panels) and diastolic area (A,B, lower panels) were assessed sequentially in the same embryos at 72, 96 and 120hpf. Images in C show embryonic hearts following treatment with flavopiridol and Cdk9-Mo (SB). Left-hand panels are bright field images of the heart, and right-hand panels are histological sections through the heart stained with haematoxylin and eosin (H&E). n=3 experiments, >10 embryos per experiment, *P<0.05, **P<0.01, ***P<0.001. Two-way ANOVA test for repeated measures followed by Bonferroni′s post-hoc test. ‘A’, atrium; BA, bulbous arteriosus; V, ventricle. Means±s.e.m. are shown in upper and lower panels of A and B.

Effects of Larp7 knockdown on cardiac structure and function. (A) Larp7-targeting morpholinos [either splice blocking (SB) or translation blocking (TB)] resulted in normal heart development, here shown in vivo (left hand panel) and following H&E staining (right hand panel). Ventricular diastolic area (B) and ejection fraction (C) in Larp7-knockdown embryos were similar to controls (Larp7 mismatch morpholino). A mild dilatation of the atrium (D) was observed in Larp7-knockdown (TB and SB Larp7-Mo) embryos. Larp7 mRNA (E) and protein (F) were significantly reduced at 48 and 96hpf. Larp7-Mo-TB (larp7 Mo) injection caused increased phosphorylation of Ser2 in the RNA polymerase II C-terminal domain (P-Ser2 CTD), suggesting an upregulation of Cdk9 activity. n=3 experiments, *P<0.05, **P<0.01, ***P<0.001, two-way ANOVA followed by Bonferroni′s post-hoc test. Means±s.e.m. are shown in B, C, D and E.

Effects of Cdk9 modulation on ventricle cardiomyocyte proliferation during early development of the zebrafish heart. Effects of flavopiridol (A, white bars, controls; black bars, flavopiridol 3µmol/l) on the total number of cardiomyocytes in the isolated embryonic zebrafish ventricle. Effects of Cdk9 morpholino (B, Cdk9-Mo-SB, Cdk-Mo) and Larp7 morpholino (C, Larp7-Mo-SB, Larp7-Mo) on total cardiomyocyte number in the embryonic ventricle (white bars, controls, appropriate mismatch morpholino; dark bars, splice-blocking morpholino. Effects of flavopiridol on the number of proliferating cardiomyocytes (D, white bars, controls; black bars, flavopiridol 3µmol/l). Representative confocal images (E) of isolated embryonic myl7:GFP hearts stained with DAPI (blue) and for phospho-Histone-H3 (PHH3, red nuclei, marking proliferating cardiomyocytes). Data are mean±s.e.m., n=3 experiments, n=5 hearts per group, *P<0.05, **P<0.01 ***P<0.001, two-way ANOVA test. Means±s.e.m. are shown in A, B, C and D.

ZFIN is incorporating published figure images and captions as part of an ongoing project. Figures from some publications have not yet been curated, or are not available for display because of copyright restrictions.

ZFIN is incorporating published figure images and captions as part of an ongoing project. Figures from some publications have not yet been curated, or are not available for display because of copyright restrictions.

Rescue of the Cdk9-knockdown phenotype using capped cdk9 mRNA or Larp7-Mo-SB. (A–C) Survival and phenotype score in embryos treated with CDK9-Mo-SB (Cdk9-Mo), LARP7-Mo-SB (Larp7-Mo), CDK9-Mo-SB+cdk9 mRNA, Cdk9-Mo-SB+Larp7-Mo-SB assessed independently during the first 120hpf (n=3 experiments, n>50 embryos per group). (D) Effects of rescuing the Cdk9-knockdown phenotype (cdk9 mRNA or Larp7-Mo-SB) on recovery of the cardiac function after laser injury (N=3, n=20–30 embryos per experiment). Two-way ANOVA and Bonferroni post-hoc test; ns, non-significant; *P<0.05, **P<0.01 and ***P<0.001. Means±s.e.m. are shown in B, C and D.