Fig. 4

ccm2l interacts genetically with the Heg-CCM pathway. (A–C) For enhancer experiments, embryos were injected with low doses of control morpholino, ccm1 morpholino and ccm2l morpholino in pairwise combinations and assayed at 52 hpf for heart morphology and function. (A) Embryos classified as “wildtype” have a heart and inflow tract comparable to uninjected embryos and strong blood circulation. “Intermediate” embryos exhibit moderate dilation of the atrium and inflow tract but maintain some level of blood circulation. “Severe” embryos have extreme dilation of the heart and inflow tract and lack blood circulation. (B and C) Compared to a control morpholino with no predicted cellular targets, MO e2i2 and MO e4i4 both increase the proportion of moderate and severe phenotypes in embryos sensitized with ccm1 morpholino. Images of embryos were taken at 10x magnification from a lateral perspective with anterior to the left. Graphs represent data pooled from at least three independent experiments. For each group, n>98 embryos. (D,E) For rescue experiments, embryos were injected with ccm2l morpholino and subsequently injected with mRNA transcribed in vitro from either wildtype ccm2 cDNA (ccm2^wt) or from cDNA corresponding to the ccm2 mutant allele ccm2^m201. (D) ccm2^wt RNA rescued circulation in a significant proportion of embryos injected with MO e2i2, while ccm2^m201 RNA did not. (E) Similarly, ccm2^wt RNA but not ccm2^m201 RNA rescued heart and inflow tract morphology in a significant proportion of embryos injected with MO e4i4. Embryos exhibiting an enlarged inflow tract and/or enlarged atrium were labeled as “dilated inflow tract/atrium.” Graphs represent data pooled from three independent experiments. For each group, n>130 embryos. p-values are calculated from a 2×2 contingency table using Fisher′s exact test. n.s., not significant.