Fig. 7

(A) Injection of 500 ng/μg cx43 mRNA in MO-cx43ATG-injected zebrafish leads to 28% (21/78, three independent experiment) embryos displaying heart failure and arrhythmia, while MO-cx43ATG-injection results in 51% (55/108, three independent experiments; p = 0.0024) affected embryos. (C) MO-spensplice injection resulted in 62% (78/126, three independent experiments) affected embryos, while co-injection with either 250 ng/μl or 500 ng/μl cx43 mRNA significantly decreased the amount of diseased embryos to 36% (52/146, three independent experiments, p < 0.0001) and 23% (28/120, three independent experiments, p < 0.0001), respectively. Embryos with pericardial edema, bradycardia, and impaired contractility were counted as affected. (B, D) Western Blot analysis of MO-cx43ATG, MO-cx43ATG + cx43 mRNA and MO1-Ctrl and MO-spensplice + cx43 mRNA injected fish confirms reconstitution of Cx43 levels in cx43- and spen morphants, respectively. (E-G) Lateral views of embryos injected with sub-phenotypic doses of MO-cx43ATG (E), MO-spensplice (F) and a co-injected embryo (G) at 72 h post fertilization (hfp). (H) Sensitizing experiment. While injection of sub-phenotypic doses of morpholino did not cause relevant phenotypic abnormalities 72 hpf, co-injection resulted in a significant supra-additive effect (79/136, three independent experiments; p < 0.0001, respectively), suggesting molecular crosstalk between Spen and Cx43. Images (B,D,E,F,G) have been cropped. A, C, H: Assessment of significance by chi-squared test. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001.