STIMULATORY EFFECT OF THE MAIZE HMGA PROTEIN ON REPORTER GENE-EXPRESSION IN MAIZE PROTOPLASTS

The high mobility group (HMG) proteins represent a class of chromosoma l non-histone proteins with an assumed influence on transcription. In this context, the effect of the maize HMGa protein on reporter gene ex pression was examined. Transient co-transformation experiments in maiz e protoplasts with plasmid constructs directing the synthesis of the m aize HMGa protein and with a luciferase reporter plasmid demonstrated a stimulatory effect of the HMGa protein on the reporter gene expressi on. Additional experiments with HMGa deletion constructs indicated tha t the HMG-Box DNA-binding motif is important for the observed effect, while the acidic carboxy-terminal domain of the HMGa protein appears t o be dispensable.