Transcriptional regulation of the Saccharomyces cerevisiae amino acid permease gene BAP2.
Uptake of branched-chain amino acids by Saccharomyces cerevisiae from media containing a preferred nitrogen source is mediated by the permeases encoded by BAP2, BAP3, and VAP1/TAT1. The transcriptional activity of the BAP2 promoter is affected by a number of genes, including SSY1, which encodes an amino acid permease homologue that is necessary for transcription of BAP2. Other genes that control BAP2 encode known (Leu3p, Tup1p) and putative (Stp1p, Stp2p) transcription factors. We present evidence that the zinc-finger proteins Stp1p and Stp2p bind directly to the BAP2 promoter. Binding of Stplp to the BAP2 promoter in vivo and in vitro indicates that the STP gene family indeed encodes transcription factors. The presence of a Leu3p binding site in the BAP2 promoter is required for full promoter activity on synthetic complete medium. The capacity of Leu3p to activate BAP2 transcription correlates with conditions that affect the level of alpha-isopropyl malate. The effect of a tup1 deletion on BAP2 transcription depends on SSY1. In an ssy1 strain, the phenotype of tup1 conforms to the well-established role of Tup1p as part of a repressor complex, but in the SSY1 strain deletion of TUP1 causes a decrease in transcription, indicating that Tup1p may also have an activating role at the BAP2 promoter. Our results thus suggest a complex interplay between several transcription factors in the expression of BAP2.
Nielsen
P S
PS
Department of Yeast Genetics, Copenhagen Valby, Denmark.
van den Hazel
B
B
Didion
T
T
de Boer
M
M
Jørgensen
M
M
Planta
R J
RJ
Kielland-Brandt
M C
MC
Andersen
H A
HA
D026905:Amino Acid Transport Systems; D001665:Binding Sites; D015152:Blotting, Northern; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal; D005838:Genotype; D047908:Intracellular Signaling Peptides and Proteins; D008293:Malates / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics; D026901:Membrane Transport Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism; D010641:Phenotype; D010957:Plasmids / Q000378:metabolism; D011401:Promoter Regions, Genetic; D016601:RNA-Binding Proteins; D012097:Repressor Proteins; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D013997:Time Factors; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D020798:Two-Hybrid System Techniques; D001616:beta-Galactosidase / Q000378:metabolism
D026905:Amino Acid Transport Systems; C097094:BAP2 protein, S cerevisiae; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D047908:Intracellular Signaling Peptides and Proteins; C063667:LEU3 protein, S cerevisiae; D008293:Malates; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D009687:Nuclear Proteins; D016601:RNA-Binding Proteins; D012097:Repressor Proteins; C120527:SSY1 protein, S cerevisiae; C074632:STP1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C421606:Stp2 protein, S cerevisiae; C066502:TUP1 protein, S cerevisiae; D015534:Trans-Activators; D014157:Transcription Factors; C005906:alpha-isopropylmalate; D001616:beta-Galactosidase