HUMAN GENE FOR THE LARGE SUBUNIT OF RIBONUCLEOTIDE REDUCTASE (RRM1) -FUNCTIONAL-ANALYSIS OF THE PROMOTER

Ribonucleotide reductase comprises two nonidentical protein subunits R 1 and R2, both of which are required for enzyme activity and show cell cycle-dependent regulation. The TATA-less promoter of the human RRM1 gene (encodes R1 protein) was examined with reference to regulatory do mains upstream of the transcription start site. A region from nt -195 to +3 was found to give maximal expression of a reporter gene when tra nsfected into the human cell line K562. Overall, this 198-bp region sh ows 58% identity with the equivalent region of the murine promoter; ho wever, it contains two 22-bp domains that were 81 and 91% identical be tween species. Electrophoretic mobility shift assays were performed us ing a fragment of the domain closest to the transcription start site. These experiments revealed that several factors were able to bind this region in a sequence-specific manner. One of these factors was shown to be Spl by specific competition and supershift using antibody to Spl . The data presented suggest that Spl is involved in the transcription of RRRM1. (C) 1995 Academic Press, Inc.