Modulation of endogenous VEGF-A expression by artificial transcription factors.

The vascular endothelial growth factor A (VEGF-A) gene is an attractive therapeutic target because both activation and repression of the gene are useful for treatment or cure of many diseases related to abnormal angiogenesis. To modulate the endogenous gene expression artificially, we previously designed a six-finger AZP to recognize a 19-bp DNA in the VEGF-A gene, and fused the AZP with a nuclear localization signal and a repressor domain to generate an artificial transcription factor (ATF). Using the ATF, we demonstrated efficient modulation of the VEGF-A expression. In the present study, we evaluate the ability of the ATF to modulate the gene expression in more detail. First we examined the ability of the ATF under hypoxia condition. ELISA of the VEGF-A protein in the culture medium revealed that the gene-delivered ATF repressed the expression rate of the VEGF-A gene under hypoxia condition.