24 research outputs found

    Consensus ABL phosphorylation sites YXXP are required for SHE function.

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    (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

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

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    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

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

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    (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

    <i>she</i> mutants show enlarged diameter of the dorsal aorta.

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    (A,B) Overall vascular patterning of she-/- mutants is normal when compared to their sibling wild-type embryos at 28 hpf. Embryos are in kdrl:GFP background. (C-F) A wider DA is observed in she mutant embryos compared to their wild-type (she+/+) siblings at 1 and 2 dpf (28 and 48 hpf respectively). Red line indicates DA diameter. (G,H) DA is narrower in she mutants at 4 dpf compared to their siblings. (I,J) Qtracker dots were injected into the circulatory system at 2 dpf (48 hpf) stage. Wider DA is apparent in she mutants (red lines), indicating enlarged vascular lumen size. (K) Diameter of the DA and PCV at 1–4 dpf in she mutants and their wild-type siblings. * phe mutant and sibling embryos were obtained by in-crossing sheci26+/-; kdrl:GFP carriers. Embryos at 1 and 2 dpf were genotyped after imaging. Embryos at 4 dpf were separated based on the phenotype, and wild-type siblings include she+/+ and she+/- embryos at this stage. Numbers at the bottom of the bars indicate the total number of embryos analyzed.</p

    Inhibition of SHE in HUVECs results in enlarged tubulogenesis.

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    (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

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

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    (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

    Hybridization chain reaction (HCR) analysis of <i>cldn5b</i> mRNA expression at 24 hpf.

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    (A,B) cldn5b (purple) and kdrl:GFP fluorescence in the trunk region of she mutant and wild-type sibling embryos. DA, dorsal aorta; PCV, posterior cardinal vein. cldn5b fluorescence is shown in A’,B’. (C) Quantification of cldn5b fluorescence in the DA. p = 0.17, Student’s t-test. Error bars show SEM. Data show combined results from two independent experiments. (TIF)</p
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