The UGA3-GLT1 intergenic region constitutes a promoter whose bidirectional nature is determined by chromatin organization in Saccharomyces cerevisiae.
Transcription of an important number of divergent genes of Saccharomyces cerevisiae is controlled by intergenic regions, which constitute factual bidirectional promoters. However, few of such promoters have been characterized in detail. The analysis of the UGA3-GLT1 intergenic region has provided an interesting model to study the joint action of two global transcriptional activators that had been considered to act independently. Our results show that Gln3p and Gcn4p exert their effect upon cis-acting elements, which are shared in a bidirectional promoter. Accordingly, when yeast is grown on a low-quality nitrogen source, or under amino acid deprivation, the expression of both UGA3 and GLT1 is induced through the action of both these global transcriptional modulators that bind to a region of the bidirectional promoter. In addition, we demonstrate that chromatin organization plays a major role in the bidirectional properties of the UGA3-GLT1 promoter, through the action of an upstream Abf1p-binding consensus sequence and a polydAdT(tract). Mutations in these cis-elements differentially affect transcription of UGA3 and GLT1, and thus alter the overall relative expression. This is the first example of an intergenic region constituting a promoter whose bidirectional character is determined by chromatin organization.
Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México.
Cecilia
C
Ishida
Cristina
C
Aranda
Lourdes
L
Valenzuela
Lina
L
Riego
Alexander
A
Deluna
Félix
F
Recillas-Targa
Patrizia
P
Filetici
Rubén
R
López-Revilla
Alicia
A
González
D000596:Amino Acids / Q000378:metabolism; D001483:Base Sequence; D050976:Basic-Leucine Zipper Transcription Factors; D002843:Chromatin / Q000737:chemistry / Q000378:metabolism*; D016384:Consensus Sequence; D021901:DNA, Intergenic / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D050790:Glutamate Synthase (NADH) / Q000235:genetics*; D008969:Molecular Sequence Data; D009584:Nitrogen / Q000378:metabolism; D017354:Point Mutation; D011067:Poly dA-dT / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D012045:Regulatory Sequences, Nucleic Acid; D012097:Repressor Proteins / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism*
C061886:ABF1 protein, S cerevisiae; D000596:Amino Acids; D050976:Basic-Leucine Zipper Transcription Factors; D002843:Chromatin; D021901:DNA, Intergenic; D004268:DNA-Binding Proteins; C501391:GCN4 protein, S cerevisiae; C071664:GLN3 protein, S cerevisiae; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C092661:UGA3 protein, S cerevisiae; D011067:Poly dA-dT; D050790:Glutamate Synthase (NADH); D009584:Nitrogen