Amino acids control mammalian gene transcription: activating transcription factor 2 is essential for the amino acid responsiveness of the CHOP promoter.
In mammals, plasma concentration of amino acids is affected by nutritional or pathological conditions. It has been well established that nutrients, and particularly amino acids, are involved in the control of gene expression. Here we examined the molecular mechanisms involved in the regulation of CHOP (a CCAAT/enhancer-binding protein [C/EBP]-related gene) expression upon amino acid limitation. We have previously shown that regulation of CHOP mRNA expression by amino acid concentration has both transcriptional and posttranscriptional components. We report the analysis of cis- and trans-acting elements involved in the transcriptional activation of the human CHOP gene by leucine starvation. Using a transient expression assay, we show that a cis-positive element is essential for amino acid regulation of the CHOP promoter. This sequence is the first described that can regulate a basal promoter in response to starvation for several individual amino acids and therefore can be called an amino acid response element (AARE). In addition, we show that the CHOP AARE is related to C/EBP and ATF/CRE binding sites and binds in vitro the activating transcription factor 2 (ATF-2) in starved and unstarved conditions. Using ATF-2-deficient mouse embryonic fibroblasts and an ATF-2-dominant negative mutant, we demonstrate that expression of this transcription factor is essential for the transcriptional activation of CHOP by leucine starvation. Altogether, these results suggest that ATF-2 may be a member of a cascade of molecular events by which the cellular concentration of amino acids can regulate mammalian gene expression.
Bruhat
A
A
U.R. 238 de Nutrition Cellulaire et Moléculaire, INRA de Theix, 63122 Saint Genès Champanelle, France.
Jousse
C
C
Carraro
V
V
Reimold
A M
AM
Ferrara
M
M
Fafournoux
P
P
D051698:Activating Transcription Factor 2; D000818:Animals; D022762:CCAAT-Enhancer-Binding Proteins; D002478:Cells, Cultured / Q000187:drug effects / Q000378:metabolism; D003470:Culture Media / Q000494:pharmacology; D017362:Cyclic AMP Response Element-Binding Protein / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000172:deficiency / Q000235:genetics* / Q000502:physiology; D004742:Enhancer Elements, Genetic; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006367:HeLa Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007930:Leucine / Q000494:pharmacology / Q000502:physiology*; D051379:Mice; D009687:Nuclear Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology; D011401:Promoter Regions, Genetic / Q000187:drug effects; D012333:RNA, Messenger / Q000096:biosynthesis; D012334:RNA, Neoplasm / Q000096:biosynthesis; D012045:Regulatory Sequences, Nucleic Acid / Q000187:drug effects; D015398:Signal Transduction; D051742:Transcription Factor CHOP; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D014158:Transcription, Genetic / Q000235:genetics / Q000502:physiology*; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism
C497105:ATF2 protein, human; D051698:Activating Transcription Factor 2; C497106:Atf2 protein, mouse; D022762:CCAAT-Enhancer-Binding Proteins; D003470:Culture Media; D017362:Cyclic AMP Response Element-Binding Protein; C497249:DDIT3 protein, human; D004268:DNA-Binding Proteins; C497250:Ddit3 protein, mouse; D009687:Nuclear Proteins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D014157:Transcription Factors; D051742:Transcription Factor CHOP; D007930:Leucine