The transcription of the SUC2 gene is regulated by glucose repression and the derepression mechanism in the yeast Saccharomyces cerevisiae. The Mig1p-Tup1p-Ssn6p repressor complex, hexokinase PII and nucleosomes are required for the repression of the SUC2 gene. | Turk J Biol 27 (2003) 233-239 © TÜB‹TAK Analysis of the Effects of Transcription Factors Gcr2p and Sgc1p on the Control of the SUC2 Gene Expression in Saccharomyces cerevisiae 1 Sezai TÜRKEL1, Tülay TURGUT2, ‹pek SAVAfiCIO⁄LU1 Department of Biology, Faculty of Arts and Sciences, Uluda¤ University, 16059, Bursa - TURKEY 2 Abant ‹zzet Baysal University, Faculty of Arts and Sciences, Department of Biology, 14280, Bolu - TURKEY Received: Abstract: The transcription of the SUC2 gene is regulated by glucose repression and the derepression mechanism in the yeast Saccharomyces cerevisiae. The Mig1p-Tup1p-Ssn6p repressor complex, hexokinase PII and nucleosomes are required for the repression of the SUC2 gene. The Snf/Swi and SAGA complexes act on Mig1p and nucleosomes in low glucose media. SUC2 transcription thus becomes activated. In this study, it is shown that the transcription factors Gcr2p and Sgc1p are also required for the high level transcription of the SUC2 gene. SUC2 transcription and the invertase synthesis decreased at significant levels in gcr2 and sgc1 mutant yeast cells. In addition, it is also shown that the derepression of the SUC2 gene transcription is very slow in gcr2 and sgc1 mutant yeast strains. The glucose repression rate seems to be normal in gcr2 and sgc1 mutants, indicating that Gcr2p and Sgc1p are essential for the high level transcription of the SUC2 gene. Key Words: Invertase, Glucose repression, GCR2, SUC2, SGC1, Saccharomyces cerevisiae, Transcription. Transkripsiyon Faktörleri Gcr2p ve Sgc1p’nin Saccharomyces cerevisiae’da SUC2 Gen ‹fadesinin Kontrolüne Etkilerinin Analizi Özet: Saccharomyces cerevisiae’da SUC2 geninin transkripsiyonu glikoz bask›lamas› ve bask›n›n kald›r›lmas› mekanizmas› ile düzenlenmektedir. Mig1p-Tup1p-Ssn6p represör kompleksi, hekzokinaz II proteini ve nükleozomlar SUC2 geninin bask›lanmas› için gereklidirler. Düflük miktarda glikoz içeren üreme ortam›nda ise Snf/Swi ve SAGA kompleksleri Mig1p .
