Mutation of putative DNA contacting amino acids in the HEY1 basic domain inactivates its function.

<p>(A) Amino acid sequence of the HEY1 basic domain and the HEY1-RK3 mutant with three amino acid exchanges (R50K, R54K, R62K) that likely contact DNA bases. (B) Immunostaining of transfected HEK293T cells with a Flag antibody confirms a preferential nuclear localization of Flag-tagged HEY1 and HEY1-RK3. (C) Real-time RT-PCR shows repression of <i>HEY1</i>, <i>BMP2</i>, <i>KLF10</i> and <i>FOXC1</i> by HEY1, but not by HEY1-RK3 (log scale). (D) ChIP analysis confirms enrichment of HEY1 binding sites in target promoters by wild type HEY1, but not by mutant HEY1-RK3 (log scale).