1. Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA

Abstract

Classical yeast genetics coupled with the cloning of regulatory genes by complementation of function^1,2 is a powerful means of identifying and isolating trans-acting regulatory elements^3–6. One such regulatory gene is ADR1 which encodes a protein required for transcriptional activation of the glucose-repressible alcohol dehydrogenase (ADH2) gene^7,8. We now report the nucleotide sequence of ADR1; it encodes a polypeptide chain of 1,323 amino acids, of which the amino-terminal 302 amino acids are sufficient to stimulate ADH2 transcription. This active amino-terminal region shows amino-acid sequence homology with the repetitive DNA-binding domain of TFIIIA⁹, an RNA polymerase III transcription factor of Xenopus laevis¹⁰. Similar domains are found in proteins encoded at the Krüppel¹¹ and Serendipity¹² loci of Drosophila melanogaster. We discuss the implications of this structural homology and suggest that a similar domain may exist in other yeast regulatory proteins such as those encoded by GAL4 (ref. 13) and PPR1 (ref. 14).