THE GLUCOSE-DEPENDENT TRANSACTIVATION ACTIVITY OF ABF1 ON THE EXPRESSION OF THE TDH3 GENE IN YEAST

Autonomously replicating sequence binding factor 1 (ABF1) has been imp licated in the control of a variety of gene expressions in Saccharomyc es cerevisiae. In this paper evidence is presented that ABF1 is involv ed in the glucose-dependent expression of the TDH3 gene which encodes glyceraldehyde-3-phosphate dehydrogenase. ABF1 binds to consensus site s located between -420 and -250, and between +77 and +200, and acts as a transactivator in an orientation-independent manner on both upstrea m and downstream sites. TDH3-lacZ fusions having an ABF1 consensus mot if showed glucose-dependent expression of TDH3, whereas in the abf1 mu tant strain JCA35 glucose-dependent expression disappeared. These find ings suggest that ABF1 functions as a glucose-dependent transactivator for the expression of the TDH3 gene.