The role of survivin in angiogenesis during zebrafish embryonic development.
BACKGROUND
Survivin is the smallest member of the inhibitor of apoptosis (IAP) gene family. Recently, the zebrafish survivin-1 gene has been cloned, showing remarkable sequence identity and similarity over the BIR domain compared with human and mouse survivin gene. Here we investigated the role of survivin in angiogenesis during zebrafish development. Morpholinos (MOs) targeting the 5' untranslated region (UTR) (SurUTR) and sequences flanking the initiation codon (SurATG) of zebrafish survivin-1 gene were injected into embryos at 1-4 cell stage. Vasculature was examined by microangiography and GFP expression in Tg(fli1:EGFP)y1 embryos.


RESULTS
In embryos co-injected with SurUTR and SurATG-MOs, vasculogenesis was intact but angiogenesis was markedly perturbed, especially in the inter-segmental vessels (ISV) and dorsal longitudinal anastomotic vessels (DLAV) of the trunk, the inner optic circle and optic veins of developing eyes and the sub-intestinal vessels. Apoptosis was increased, as shown by TUNEL staining and increase in caspase-3 activity. Efficacy of SurUTR and SurATG-MOs was demonstrated by translation inhibition of co-injected 5'UTR survivin:GFP plasmids. The phenotypes could be recapitulated by splice-site MO targeting the exon2-intron junction of survivin gene and rescued by survivin mRNA. Injection of human vascular endothelial growth factor (VEGF) protein induced ectopic angiogenesis and increased survivin expression, whereas treatment with a VEGF receptor inhibitor markedly reduced angiogenesis and suppressed survivin expression.


CONCLUSIONS
Survivin is involved in angiogenesis during zebrafish development and may be under VEGF regulation.
Ma
Alvin Ch
ACh
Department of Medicine, University of Hong Kong, Hong Kong. h0025231@hkusua.hku.hk <h0025231@hkusua.hku.hk>
Lin
Rachel
R
Chan
Po-Kwok
PK
Leung
Joseph C K
JC
Chan
Loretta Y Y
LY
Meng
Anming
A
Verfaillie
Catherine M
CM
Liang
Raymond
R
Leung
Anskar Y H
AY
D000818:Animals; D004625:Embryo, Nonmammalian / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D051034:Inhibitor of Apoptosis Proteins / Q000235:genetics*; D018919:Neovascularization, Physiologic / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics / Q000502:physiology
D051034:Inhibitor of Apoptosis Proteins; D042461:Vascular Endothelial Growth Factor A