Consensus ABL phosphorylation sites YXXP are required for SHE function.

(A) Consensus ABL phosphorylation sites are conserved between zebrafish, mice and humans. (B) Vascular endothelial expression of a mutant construct fli1:sheFXXP-2A-mCherry, where all four consensus tyrosines have been substituted into phenylalanine, fails to rescue the pericardial edema in she mutants at 4 dpf. The first bar showing she-/- embryos (no Tg) is copied from Fig 3I. ****pfli1:sheFXXP-2A-mCherry embryos and sibling mCherry-negative embryos at 28 hpf. 5 measurements were performed in each embryo, which were then averaged for statistical calculations. 2 replicate experiments were performed, shown in different colors. n corresponds to the number of embryos. Mean ± SD is shown. *p<0.05, Student’s t-test.</p

Expression of <i>abl1</i> and <i>abl2</i> in different cell types during zebrafish embryogenesis based on single-cell RNA seq expression atlas.

Data were generated by Daniocell atlas https://daniocell.nichd.nih.gov/ [31]. (TIF)</p

Numerical original data used for graphs and summary statistics.

Tab numbers in the Excel table match to the figure numbers of corresponding graphs. (XLSX)</p

A proposed model for SHE and ABL signaling during vascular tubulogenesis.

Activated ABL promotes enlarged vascular lumen through a downstream effector P-CRKL which increases endothelial cell proliferation and increases Cldn5 expression, thus affecting tight junctions and cell adhesion. Activated ABL phosphorylates SHE, which then interacts with ABL to dampen its activity resulting in the lumen of appropriate size.</p

Inhibition of SHE in HUVECs results in enlarged tubulogenesis.

(A-F) HUVEC cells were transfected with either control or SHE siRNA and analyzed in 3D collagen matrix assay at 48 (A-C) or 72 h (D-F) after transfection. The values (± standard deviation) are derived from 6–7 representative fields from 3 replicate wells where total EC tube area was measured. *** pS11 Fig. (H) Relative intensity ratio in siSHE / siControl samples. Note increased intensity in pPAK4 and pCRKL samples compared to siControl (which equals to 1); *p<0.05, **p<0.01, Student’s t-test.</p

CRISPR/ Cas9 knockdown of <i>abl1</i> and <i>abl2</i> function results in reduced DA size.

(A) A diagram illustrating the targeting sites of sgRNAs against abl1 and abl2 genes. Each gRNA was more than 90% effective based on DNA sequencing analysis. (B-D) Analysis of DA size in kdrl:GFP embryos at 28 hpf. Note the reduced DA diameter in embryos injected with abl1 and 2 gRNA mixture. Data from two replicate experiments are shown in different colors. Mean±SD is shown. **p (TIF)</p

Blood flow does not affect <i>she</i> expression or <i>she</i> mutant phenotype.

(A,B) In situ hybridization analysis for she expression at 28 hpf in tnnt2 MO-injected embryos and uninjected controls. Trunk region is shown, anterior is to the left. Numbers in the lower right indicate embryos that showed normal expression pattern out of the total number of embryos in 3 replicate experiments. (C-H) DA size analysis at 28 hpf in wt (she+/+) and she-/- sibling embryos, injected with tnnt2 MO, compared to uninjected controls. Embryos were obtained from cross of she+/- parents in kdrl:GFP background and subsequently genotyped. Note that DA diameter is greatly reduced in tnnt2 MO-injected embryos compared to wild-type uninjected embryos, and increased in she mutants, injected with tnnt2 MO compared to wild-type embryos injected with tnnt2 MO. Data are combined from 3 replicate experiments, shown in different color. Mean±SD is shown. The number of embryos analyzed is shown at the bottom of each bar. The same wt+tnnt2 MO embryos were used for comparisons in (G) and (H). *p (TIF)</p

Diagrams and sequence chromatograms of <i>she</i>^<i>ci26</i> and ^<i>ci30</i> mutations.

(A) sheci26 mutants have a 7 bp deletion. Alignment of wild-type and sheci26 mutant sequences is shown starting with the first coding ATG. (B) Genomic DNA sequence chromatogram of sheci30 mutants. (C) sheci30 mutants carry a 575 bp deletion and 24 bp insertion present between exons 3 and 4 within she gene. (TIF)</p

<i>she</i> mutants display pericardial edema and loss of blood circulation.

(A) Zebrafish SHE protein diagram. she ci26 and ci30 mutant alleles are predicted to result in a frameshift and premature stop codons. SH2 domain and consensus tyrosine ABL phosphorylation sites are shown. (B-E) In situ hybridization analysis of she expression in wild-type embryos at 24, 48, 72 and 96 hpf stages. Note its expression in the dorsal aorta (arrows), intersegmental vessels, lateral line primordium (arrowhead, B) and neuromasts (arrowheads, C-E). (F-I) In situ hybridization analysis of she expression in she mutants at 24 hpf. Note that she expression is unaffected in sheci26 embryos while it is strongly reduced in sheci30 embryos. Homozygous sheci26 mutant embryos were obtained by an incross of sheci26-/-; fli1a:she-2A-mCherry; kdrl:GFP parents (which are viable due to fli1a:she-2A-mCherry rescue) and selected for mCherry negative embryos. Wild-type control embryos were obtained by incross of sibling wt; fli1a:she-2A-mCherry parents and selected for mCherry-negative embryos. sheci30 embryos were obtained by incross of sheci30+/- parents and genotyped after in situ hybridization. 25% (10 out of 40) embryos showed strong reduction in she expression which correlated with the mutant phenotype. (J-M) Brightfield images of sheci26 and sheci30 mutant embryos and their siblings (wild-type and or heterozygous) at 4 dpf. Note the pericardial edema (arrowheads) in the mutant embryos. Embryos were obtained by the incross of heterozygous parents in kdrl:GFP background. 24.9% (265 out of 1064) and 24.2% (80 out of 330) embryos obtained in sheci26 or sheci30 incross, respectively, showed this phenotype. A subset of embryos was genotyped to confirm the correlation between the phenotype and genotype.</p

Inhibitors of Abl signaling reduce DA diameter in wild-type and <i>she</i> mutant embryos.

(A-E) Dorsal aorta diameter at 28 hpf is reduced in kdrl:GFP embryos treated with 5 μM Dasatinib or 1 μM GNF-7 compared to controls treated with 0.1% DMSO. (F-H) Embryos treated with 5 μM Dasatinib (F-H, left) or 1 μM GNF-7 (H, right) exhibit narrower DA at 4 dpf compared to controls treated with 1% DMSO (GNF-7) or 2% DMSO (Dasatinib treatments). (I-K) The number of cells in the DA is reduced in embryos at 28 hpf treated with 1 μM GNF-7 compared to control embryos treated with 0.1% DMSO. (L-O) GNF-7 treatment reverses DA enlargement in she mutant embryos. she+/-; kdrl:GFP adults were crossed to obtain she mutant embryos. Embryos were treated starting at 6 hpf with either 0.5 μM GNF-7 or 0.1% DMSO. Embryos were imaged at approximately 55 hpf and subsequently genotyped. DA measurements were performed blinded. Mid-trunk region is shown, anterior is to the left. Note the slightly wider DA (red line) in she-/- mutant embryos compared to wild-type (she+/+) siblings. DA is reduced in both wild-type and she mutant embryos treated with GNF-7. (P) Quantification of DA diameter in wild-type or she mutant embryos treated with GNF-7 or DMSO. In all graphs mean±SD is shown. Data points (shown in different colors) are combined from 2 (left graph C,H,K) or 3 (right graph C,P) independent experiments. Total number of embryos analyzed is shown at the bottom of each bar. *p<0.05, **p<0.01, ***p<0.001, ****p<0.0001, NS–not significant, Student’s t-test (C,H,K), or one-way ANOVA test, followed by multiple comparisons Fisher’s LSD (P).</p