Characterization of a novel form of angiopoietin-2 (Ang-2B) and expression of VEGF and angiopoietin-2 during chicken testicular development and regression.
The complex process of angiogenesis is controlled by the vascular endothelial growth factor (VEGF) and its receptors and by the recently isolated angiopoietin-1 (Ang-1) and angiopoietin-2 (Ang-2) that signal through the transmembrane endothelial receptor tyrosine kinase Tie2. We report here the characterization of a novel form of Ang-2 (Ang-2B) with a truncated amino-terminal domain resulting from an alternative splicing of the gene. While previous reports have found the expression of Ang-2 limited to the embryo, female reproductive organs, and tumor tissues, we have observed striking changes in Ang-2 expression during chicken testicular development and regression. The expression of Ang-2 and VEGF is abundant in prepuberal testis and low in quiescent adult testis. Testicular regression is accompanied by high expression of Ang-2 and very low expression of VEGF. These observations are in accordance with the proposal that Ang-2 induces angiogenesis in the presence of VEGF and vascular regression in its absence.
Institut d'Investigacions Biomèdiques August Pi i Sunyer, Facultat de Medicina, Universitat de Barcelona, Casanova 143, Barcelona, 08036, Spain. mezquita@medicina.ub.es
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D000595:Amino Acid Sequence; D042702:Angiopoietin-2; D000818:Animals; D001483:Base Sequence; D002642:Chick Embryo; D002645:Chickens; D018076:DNA, Complementary; D016228:Endothelial Growth Factors / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D008222:Lymphokines / Q000235:genetics*; D008297:Male; D008969:Molecular Sequence Data; D018919:Neovascularization, Physiologic / Q000502:physiology; D011506:Proteins / Q000235:genetics* / Q000502:physiology; D017386:Sequence Homology, Amino Acid; D013737:Testis / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D042702:Angiopoietin-2; D018076:DNA, Complementary; D016228:Endothelial Growth Factors; D008222:Lymphokines; D011506:Proteins; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors