Localization and lnteraction of the cís-Acting Elements for Abscisic Acid, VIVIPAROUSI, and Light Activation of the C1 Gene of Maize

The C7 regulatory gene of the maize anthocyanin pathway is regulated by a combination of developmental and environmental signals that include the Viviparousl (Vpl) gene, abscisic acid (ABA), and light. Using protoplast electroporation and particle bombardment assays, we have defined cis-acting elements that are necessary and sufficient for the activation of C7 by ABA, VP1, and light, respectively. The sequence from positions -142 to -132 (CGTCCATGCAT) is essential for VPl activation, whereas a larger overlapping element from -147 to -132 (CGTGTCGTCCATGCAT) is necessary and sufficient for activation by ABA. A separate light (blue and red)-responsive cis element is located between positions -116 and -59. Light interacts synergistically with the ABA and VP1 responses in transient expression assays, suggesting that combinatorial interaction between modules plays a role in integrating these signals in the developing seed.