Etv2 and fli1b function together as key regulators of vasculogenesis and angiogenesis.
OBJECTIVE
The E26 transformation-specific domain transcription factor Etv2/Etsrp/ER71 is a master regulator of vascular endothelial differentiation during vasculogenesis, although its later role in sprouting angiogenesis remains unknown. Here, we investigated in the zebrafish model a role for Etv2 and related E26 transformation-specific factors, Fli1a and Fli1b in developmental angiogenesis.


RESULTS
Zebrafish fli1a and fli1b mutants were obtained using transposon-mediated gene trap approach. Individual fli1a and fli1b homozygous mutant embryos display normal vascular patterning, yet the angiogenic recovery observed in older etv2 mutant embryos does not occur in embryos lacking both etv2 and fli1b. Etv2 and fli1b double-deficient embryos fail to form any angiogenic sprouts and show greatly increased apoptosis throughout the axial vasculature. In contrast, fli1a mutation did not affect the recovery of etv2 mutant phenotype. Overexpression analyses indicate that both etv2 and fli1b, but not fli1a, induce the expression of multiple vascular markers and of each other. Temporal inhibition of Etv2 function using photoactivatable morpholinos indicates that the function of Etv2 and Fli1b during angiogenesis is independent from the early requirement of Etv2 during vasculogenesis. RNA-Seq analysis and chromatin immunoprecipitation suggest that Etv2 and Fli1b share the same transcriptional targets and bind to the same E26 transformation-specific sites.


CONCLUSIONS
Our data argue that there are 2 phases of early vascular development with distinct requirements of E26 transformation-specific transcription factors. Etv2 alone is required for early vasculogenesis, whereas Etv2 and Fli1b function redundantly during late vasculogenesis and early embryonic angiogenesis.
From the Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, OH (M.P.C.); Division of Developmental Biology (M.P.C., J.-S.P.), Department of Pediatrics (S.S.), Department of Pediatric Urology (J.-S.P.), Cincinnati Children's Hospital Medical Center, OH; Department of Biology, Temple University, Philadelphia, PA (V.G., J.B., D.B.); Department of Genetics, Development and Cell Biology, Iowa State University, Ames (H.-K.L., J.J.E.); Department of Zoology, Faculty of Natural Sciences, Vilnius University, Vilnius, Lithuania (V.G.); and Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN (S.C.E.).
Michael P
MP
Craig
From the Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, OH (M.P.C.); Division of Developmental Biology (M.P.C., J.-S.P.), Department of Pediatrics (S.S.), Department of Pediatric Urology (J.-S.P.), Cincinnati Children's Hospital Medical Center, OH; Department of Biology, Temple University, Philadelphia, PA (V.G., J.B., D.B.); Department of Genetics, Development and Cell Biology, Iowa State University, Ames (H.-K.L., J.J.E.); Department of Zoology, Faculty of Natural Sciences, Vilnius University, Vilnius, Lithuania (V.G.); and Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN (S.C.E.).
Viktorija
V
Grajevskaja
From the Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, OH (M.P.C.); Division of Developmental Biology (M.P.C., J.-S.P.), Department of Pediatrics (S.S.), Department of Pediatric Urology (J.-S.P.), Cincinnati Children's Hospital Medical Center, OH; Department of Biology, Temple University, Philadelphia, PA (V.G., J.B., D.B.); Department of Genetics, Development and Cell Biology, Iowa State University, Ames (H.-K.L., J.J.E.); Department of Zoology, Faculty of Natural Sciences, Vilnius University, Vilnius, Lithuania (V.G.); and Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN (S.C.E.).
Hsin-Kai
HK
Liao
From the Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, OH (M.P.C.); Division of Developmental Biology (M.P.C., J.-S.P.), Department of Pediatrics (S.S.), Department of Pediatric Urology (J.-S.P.), Cincinnati Children's Hospital Medical Center, OH; Department of Biology, Temple University, Philadelphia, PA (V.G., J.B., D.B.); Department of Genetics, Development and Cell Biology, Iowa State University, Ames (H.-K.L., J.J.E.); Department of Zoology, Faculty of Natural Sciences, Vilnius University, Vilnius, Lithuania (V.G.); and Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN (S.C.E.).
Jorune
J
Balciuniene
From the Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, OH (M.P.C.); Division of Developmental Biology (M.P.C., J.-S.P.), Department of Pediatrics (S.S.), Department of Pediatric Urology (J.-S.P.), Cincinnati Children's Hospital Medical Center, OH; Department of Biology, Temple University, Philadelphia, PA (V.G., J.B., D.B.); Department of Genetics, Development and Cell Biology, Iowa State University, Ames (H.-K.L., J.J.E.); Department of Zoology, Faculty of Natural Sciences, Vilnius University, Vilnius, Lithuania (V.G.); and Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN (S.C.E.).
Stephen C
SC
Ekker
From the Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, OH (M.P.C.); Division of Developmental Biology (M.P.C., J.-S.P.), Department of Pediatrics (S.S.), Department of Pediatric Urology (J.-S.P.), Cincinnati Children's Hospital Medical Center, OH; Department of Biology, Temple University, Philadelphia, PA (V.G., J.B., D.B.); Department of Genetics, Development and Cell Biology, Iowa State University, Ames (H.-K.L., J.J.E.); Department of Zoology, Faculty of Natural Sciences, Vilnius University, Vilnius, Lithuania (V.G.); and Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN (S.C.E.).
Joo-Seop
JS
Park
From the Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, OH (M.P.C.); Division of Developmental Biology (M.P.C., J.-S.P.), Department of Pediatrics (S.S.), Department of Pediatric Urology (J.-S.P.), Cincinnati Children's Hospital Medical Center, OH; Department of Biology, Temple University, Philadelphia, PA (V.G., J.B., D.B.); Department of Genetics, Development and Cell Biology, Iowa State University, Ames (H.-K.L., J.J.E.); Department of Zoology, Faculty of Natural Sciences, Vilnius University, Vilnius, Lithuania (V.G.); and Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN (S.C.E.).
Jeffrey J
JJ
Essner
From the Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, OH (M.P.C.); Division of Developmental Biology (M.P.C., J.-S.P.), Department of Pediatrics (S.S.), Department of Pediatric Urology (J.-S.P.), Cincinnati Children's Hospital Medical Center, OH; Department of Biology, Temple University, Philadelphia, PA (V.G., J.B., D.B.); Department of Genetics, Development and Cell Biology, Iowa State University, Ames (H.-K.L., J.J.E.); Department of Zoology, Faculty of Natural Sciences, Vilnius University, Vilnius, Lithuania (V.G.); and Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN (S.C.E.).
Darius
D
Balciunas
From the Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, OH (M.P.C.); Division of Developmental Biology (M.P.C., J.-S.P.), Department of Pediatrics (S.S.), Department of Pediatric Urology (J.-S.P.), Cincinnati Children's Hospital Medical Center, OH; Department of Biology, Temple University, Philadelphia, PA (V.G., J.B., D.B.); Department of Genetics, Development and Cell Biology, Iowa State University, Ames (H.-K.L., J.J.E.); Department of Zoology, Faculty of Natural Sciences, Vilnius University, Vilnius, Lithuania (V.G.); and Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN (S.C.E.). Saulius.Sumanas@cchmc.org.
Saulius
S
Sumanas
D042501:Angiogenic Proteins / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D030801:Animals, Genetically Modified; D017209:Apoptosis; D001665:Binding Sites; D004625:Embryo, Nonmammalian / Q000098:blood supply / Q000378:metabolism; D042783:Endothelial Cells / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D005838:Genotype; D060172:Morpholinos / Q000378:metabolism; D009154:Mutation; D018919:Neovascularization, Physiologic; D010641:Phenotype; D011401:Promoter Regions, Genetic; D051789:Proto-Oncogene Protein c-fli-1 / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D015027:Zebrafish / Q000196:embryology / Q000235:genetics / Q000378:metabolism; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*
D042501:Angiogenic Proteins; C509408:Etv2 protein, zebrafish; C000598206:Fli1b protein, zebrafish; D060172:Morpholinos; D051789:Proto-Oncogene Protein c-fli-1; D014157:Transcription Factors; D029961:Zebrafish Proteins
ETS transcription factor; angiogenesis; vasculogenesis; zebrafish