Transcriptional activators Cat8 and Sip4 discriminate between sequence variants of the carbon source-responsive promoter element in the yeast Saccharomyces cerevisiae.
The structural genes for gluconeogenesis in the yeast Saccharomyces cerevisiae are activated by the carbon source-responsive element (CSRE) found in the respective upstream regions. Regulatory genes CAT8 and SIP4 both encode zinc-cluster proteins which can bind to CSRE motifs and activate target genes under conditions of glucose deprivation. In this work, we describe a functional analysis of sequence variants containing single mutations within the strongly activating CSRE(ICL1) motif. While the sequence CCNNNNNNCCG was required as the minimal UAS for gene activation by both Cat8 and Sip4, the activators responded differently to sequence variations in the central part of the CSRE. Our results allowed us to derive a consensus sequence for efficient gene activation by Cat8 (YCCNYTNRKCCG), while a more specific motif is required for activation by Sip4 (TCCATTSRTCCGR). Although their zinc cluster domains are clearly related, Cat8 and Sip4 are not isofunctional. This conclusion is further supported by the finding that biosynthetic derepression of Cat8 in the presence of a nonfermentable carbon source precedes that of Sip4 by about 90 min.
Roth
Stephanie
S
Institut für Mikrobiologie, Abteilung Genetik und Biochemie, Ernst-Moritz-Arndt-Universität, Jahnstrasse 15a, 17487, Greifswald, Germany.
Kumme
Jacqueline
J
Schüller
Hans-Joachim
HJ
D050976:Basic-Leucine Zipper Transcription Factors; D016384:Consensus Sequence / Q000235:genetics; D024202:Electrophoretic Mobility Shift Assay; D005786:Gene Expression Regulation / Q000235:genetics / Q000502:physiology; D005943:Gluconeogenesis / Q000235:genetics; D010957:Plasmids; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011994:Recombinant Proteins / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics*; D015534:Trans-Activators / Q000235:genetics*; D015533:Transcriptional Activation
D050976:Basic-Leucine Zipper Transcription Factors; C092600:CAT8 protein, S cerevisiae; D011994:Recombinant Proteins; C099279:SIP4 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators