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The UGA3‐GLT1 intergenic region constitutes a promoter whose bidirectional nature is determined by chromatin organization in Saccharomyces cerevisiae
Author(s) -
Ishida Cecilia,
Aranda Cristina,
Valenzuela Lourdes,
Riego Lina,
DeLuna Alexander,
RecillasTarga Félix,
Filetici Patrizia,
LópezRevilla Rubén,
González Alicia
Publication year - 2006
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2006.05055.x
Subject(s) - biology , promoter , chromatin , saccharomyces cerevisiae , intergenic region , genetics , transcription (linguistics) , gene , transcriptional regulation , transcription factor , gene expression , genome , linguistics , philosophy
Summary 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.