Fig. 6

sox7 synergizes with hey2 and functions upstream of Notch ICD in LDA development. (A) The partially penetrant short-loop phenotype of both sox7^hu5626 mutants (n=104) and hey2 morphants (0.3ng, n=63) is exacerbated when the hey2 MO is injected into a sox7^hu5626+/- in-cross (n=35). Bars show the percentage of embryos from a representative experiment. (B) Schematic diagram of Hey2, indicating the TALEN target site in exon 2, which is upstream of the coding region of the basic helix-loop-helix (bHLH) DNA-binding domain and the orange (Or) domain. (C) Transient injections of 10pg per embryo hey2 TALEN mRNA into wild-type and sox7^hu5626 heterozygous in-cross. There is a moderate enhancement of penetrance of the short-loop phenotype in sox7^hu5626 in-cross injected with hey2 TALEN (n=140 embryos) compared with un-injected sox7^hu5626 in-cross (n=100 embryos) and hey2 TALEN injections into wild-type embryos (n=90 embryos). (D) Arterial specific UAS:NICD overexpression using the dll4:Gal4 driver line significantly (Student′s t-test, P=0.004) rescues the short-loop circulatory phenotype in sox7 mutants: short-loop phenotype in 27% of mutants without NICD overexpression (n=69 embryos) and in 3% with NICD overexpression (n=44 embryos). Bars represent pooled embryos of three independent experiments (total of 300 embryos). (A,C,D) Embryos were analyzed at 2.5dpf. Phenotypes classified as ‘others’ are edema, total lack of circulation and/or shunts in trunk region.