MOLECULAR DISSECTION OF THE AGAMOUS CONTROL REGION SHOWS THAT CIS-ELEMENTS FOR SPATIAL REGULATION ARE LOCATED INTRAGENICALLY

AGAMOUS (AG) is an Arabidopsis MADS box gene required for the normal d evelopment of the internal two whorls of the flower. AG RNA accumulate s in distinct patterns early and late in flower development, and sever al genes have been identified as regulators of AG gene expression base d on altered AG RNA accumulation in mutants. To understand AG regulato ry circuits, we are now identifying cis regulatory domains by characte rizing AG::beta-glucuronidase (GUS) gene fusions. These studies show t hat a normal AG::GUS staining pattern is conferred by a 9.8-kb region encompassing 6 kb of upstream sequences and 3.8 kb of intragenic seque nces. Constructs lacking the 3.8-kb intragenic sequences confer a GUS staining pattern that deviates both spatially and temporally from norm al AG expression. The GUS staining patterns in the mutants for the thr ee negative regulators of AG, apetala2, leunig, and curly leaf, showed the predicted change of expression for the construct containing the i ntragenic sequences, but no significant change was observed for the co nstructs lacking this intragenic region. These results suggest that in tragenic sequences are essential for AG regulation and that these intr agenic sequences contain the ultimate target sites for at least some o f the known regulatory molecules.