Abstract
E2-2 belongs to the basic helix-loop-helix (bHLH) family of transcription factors. E2-2 associates with inhibitor of DNA binding (Id) 1, which is involved in angiogenesis. In this paper, we demonstrate that E2-2 interacts with Id1 and provide evidence that this interaction potentiates angiogenesis. Mutational analysis revealed that the HLH domain of E2-2 is required for the interaction with Id1 and vice versa. In addition, Id1 interfered with E2-2-mediated effects on luciferase reporter activities. Interestingly, injection of E2-2-expressing adenoviruses into Matrigel plugs implanted under the skin blocked in vivo angiogenesis. In contrast, the injection of Id1-expressing adenoviruses rescued E2-2-mediated inhibition of in vivo angiogenic reaction. Consistent with the results of the Matrigel plug assay, E2-2 could inhibit endothelial cell (EC) migration, network formation, and proliferation. On the other hand, knockdown of E2-2 in ECs increased EC migration. The blockade of EC migration by E2-2 was relieved by exogenous expression of Id1. We also demonstrated that E2-2 can perturb VEGFR2 expression via inhibition of VEGFR2 promoter activity. This study suggests that E2-2 can maintain EC quiescence and that Id1 can counter this effect.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / genetics
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Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / metabolism*
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Blotting, Western
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COS Cells
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Cells, Cultured
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Chlorocebus aethiops
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Embryo, Mammalian / cytology
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Embryo, Mammalian / metabolism
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Endothelium, Vascular / physiology*
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Fluorescent Antibody Technique, Indirect
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Humans
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Immunoprecipitation
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Inhibitor of Differentiation Protein 1 / genetics
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Inhibitor of Differentiation Protein 1 / metabolism*
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Mice
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Neovascularization, Pathologic / metabolism
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Neovascularization, Pathologic / prevention & control*
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Promoter Regions, Genetic
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RNA, Small Interfering / pharmacology
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Reverse Transcriptase Polymerase Chain Reaction
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TCF Transcription Factors / antagonists & inhibitors
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TCF Transcription Factors / genetics
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TCF Transcription Factors / metabolism*
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Transcription Factor 4
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Transcription Factor 7-Like 2 Protein
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Transcription, Genetic
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Two-Hybrid System Techniques
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Vascular Endothelial Growth Factor Receptor-2 / genetics
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Vascular Endothelial Growth Factor Receptor-2 / metabolism
Substances
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Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
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ID1 protein, human
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Idb1 protein, mouse
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Inhibitor of Differentiation Protein 1
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RNA, Small Interfering
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TCF Transcription Factors
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TCF7L2 protein, human
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Tcf4 protein, mouse
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Tcf7l2 protein, mouse
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Transcription Factor 4
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Transcription Factor 7-Like 2 Protein
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Vascular Endothelial Growth Factor Receptor-2