Extensive genetic analyses of the maize anthocyanin pathway have revealed multiple target genes, whose expression is coordinately controlled by several regulatory genes. Our goal is to understand the mechanisms by which the transcription of the genes encoding the anthocyanin biosynthetic enzymes is coordinately controlled by three regulatory genes, b, c1, and a3. The proposed in vivo and in vitro experiments should enable us to begin to distinguish between possible models for how the regulatory proteins are interacting to control transcription. Our specific aims are to : 1) mutationally dissect the regions of C1 and B required for their interaction, 2) identify other proteins involved, 3) develop in vitro assays for analyzing B and C1 protein/protein interactions, 4) assess whether the B and C1 proteins interact directly with structural gene regulatory sites, 5) identify the cis-acting sites required for B and C1 regulation of uncharacterized structural gene promoters, 6) identify functionally important regions of B using available transposable element insertions, 7) determine if a3 is acting at the transcriptional level and if so, clone and characterize a3. %%% Principles of gene regulation learned from these studies should apply to other systems where a combined genetic and molecular approach is not yet feasible.
