REQUIREMENT OF MULTIPLE DNA-PROTEIN INTERACTIONS FOR INDUCIBLE EXPRESSION OF RNR3 GENE IN SACCHAROMYCES-CEREVISIAE IN RESPONSE TO DNA-DAMAGE

The RNR3 gene encodes the large subunit of ribonucleotide reductase. T ranscription of this gene is induced 12-fold in response to DNA damage or by a DNA replication blocker. To investigate cis-acting regulation , deletion analysis of the promoter region of the RNR3 gene was perfor med and we identified two upsteam-repressing sequences in the RNR3 reg ulatory region. An 18-base-pairs fragment, termed DNA-damage responsiv e element 1 (DRE1) located between -212 and -194 in this region was fo und to be essential for the induction of RNR3. This fragment contained a negatively acting sequence where a protein factor bound to the regi on during normal growth but disappeared by exposure to 4-nitroquinolin e-1-oxide. The other repressive element homologue to DRE1 was located at -263 to -254. One possible upstream-activating sequence which regul ates the basal expression of RNR3 was also found. These results show t hat at least three potential cis-elements are necessary for the induci ble expression of yeast RNR3 in response to DNA damage. (C) 1996 Acade mic Press, Inc.