THE RAG3 GENE OF KLUYVEROMYCES-LACTIS IS INVOLVED IN THE TRANSCRIPTIONAL REGULATION OF GENES-CODING FOR ENZYMES IMPLICATED IN PYRUVATE UTILIZATION AND GENES OF THE BIOSYNTHESIS OF THIAMINE PYROPHOSPHATE

The RAG3 gene of Kluyveromyces lactis, a homolog of PDC2 of Saccharomy ces cerevisiae, is known to be a regulator of the pyruvate decarboxyla se gene KIPDC1. We have identified new target genes for Rag3p. The RAG 3 gene product was found to be required for the transcription of two g enes of the biosynthetic pathway of thiamine (a cofactor of pyruvate d ecarboxylase). Conversely, the RAG3 gene product partially repressed t he expression of the pyruvate dehydrogenase gene KIPDA1. Therefore, RA G3 may act as a general regulator in the balance of the two alternativ e pathways of pyruvate metabolism in yeast. (C) 1998 Federation of Eur opean Microbiological Societies. Published by Elsevier Science B.V. Al l rights reserved.