Abstract
BACKGROUND: Acetylation of promoter nucleosomes is tightly correlated and mechanistically linked to gene activity. However, transcription is not necessary for promoter acetylation. It seems, therefore, that external and endogenous stimuli control histone acetylation and by this contribute to gene regulation. Photosynthetic genes in plants are excellent models with which to study the connection between stimuli and chromatin modifications because these genes are strongly expressed and regulated by multiple stimuli that are easily manipulated. We have previously shown that acetylation of specific histone lysine residues on the photosynthetic phosphoenolpyruvate carboxylase (Pepc) promoter in maize is controlled by light and is independent of other stimuli or gene activity. Acetylation of upstream promoter regions responds to a set of other stimuli which include the nutrient availability of the plant. Here, we have extended these studies by analysing histone acetylation during the diurnal and circadian rhythm of the plant. RESULTS: We show that histone acetylation of individual lysine residues is removed from the core promoter before the end of the illumination period which is an indication that light is not the only factor influencing core promoter acetylation. Deacetylation is accompanied by a decrease in gene activity. Pharmacological inhibition of histone deacetylation is not sufficient to prevent transcriptional repression, indicating that deacetylation is not controlling diurnal gene regulation. Variation of the Pepc promoter activity during the day is controlled by the circadian oscillator as it is maintained under constant illumination for at least 3 days. During this period, light-induced changes in histone acetylation are completely removed from the core promoter, although the light stimulus is continuously applied. However, acetylation of most sites on upstream promoter elements follows the circadian rhythm. CONCLUSION: Our results suggest a central role of upstream promoter acetylation in the quantitative regulation of gene expression in this model gene. Induced core promoter acetylation is dispensable for the highest gene expression in the diurnal and circadian rhythm.
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Claims 8
Claim · model-written summary
Histone acetylation of individual lysine residues is removed from the Pepc core promoter in maize before the end of the illumination period.
- Organ / stage
- core promotere1
- Gene
- Pepce0
- Outcome
- histone acetylatione1
- Direction
- removede1
- Qualifier
- before the end of the illumination periode1
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“photosynthetic phosphoenolpyruvate carboxylase (Pepc) promoter in maize”
e1“histone acetylation of individual lysine residues is removed from the core promoter before the end of the illumination period”
Claim · model-written summary
Deacetylation of the Pepc promoter is accompanied by a decrease in gene activity in maize.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“photosynthetic phosphoenolpyruvate carboxylase (Pepc) promoter in maize”
e2“Deacetylation is accompanied by a decrease in gene activity”
Claim · model-written summary
Pharmacological inhibition of histone deacetylation did not prevent transcriptional repression of the Pepc promoter in maize.
- Treatment
- Pharmacological inhibition of histone deacetylatione3
- Gene
- Pepce0
- Outcome
- transcriptional repressione3
- Direction
- not sufficient to prevente3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“photosynthetic phosphoenolpyruvate carboxylase (Pepc) promoter in maize”
e3“Pharmacological inhibition of histone deacetylation is not sufficient to prevent transcriptional repression”
Claim · model-written summary
Variation of the Pepc promoter activity during the day is controlled by the circadian oscillator and maintained under constant illumination for at least 3 days.
- Treatment
- constant illuminatione4
- Gene
- Pepce0
- Outcome
- Variation of the Pepc promoter activitye4
- Direction
- maintainede4
- Qualifier
- circadian oscillatore4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“photosynthetic phosphoenolpyruvate carboxylase (Pepc) promoter in maize”
e4“Variation of the Pepc promoter activity during the day is controlled by the circadian oscillator as it is maintained under constant illumination for at least 3 days”
Claim · model-written summary
Under constant illumination, light-induced changes in histone acetylation are completely removed from the core promoter.
- Organ / stage
- core promotere5
- Outcome
- light-induced changes in histone acetylatione5
- Direction
- completely removede5
- Qualifier
- although the light stimulus is continuously appliede5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“photosynthetic phosphoenolpyruvate carboxylase (Pepc) promoter in maize”
e5“light-induced changes in histone acetylation are completely removed from the core promoter, although the light stimulus is continuously applied”
Claim · model-written summary
Acetylation of most sites on upstream promoter elements of the Pepc promoter follows the circadian rhythm in maize.
- Organ / stage
- upstream promoter elementse6
- Gene
- Pepce0
- Outcome
- acetylation of most sitese6
- Direction
- followse6
- Qualifier
- circadian rhythme6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“photosynthetic phosphoenolpyruvate carboxylase (Pepc) promoter in maize”
e6“acetylation of most sites on upstream promoter elements follows the circadian rhythm”
Claim · model-written summary
Induced core promoter acetylation is dispensable for the highest gene expression in the diurnal and circadian rhythm in maize.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“photosynthetic phosphoenolpyruvate carboxylase (Pepc) promoter in maize”
e7“Induced core promoter acetylation is dispensable for the highest gene expression in the diurnal and circadian rhythm”
Claim · model-written summary
Upstream promoter acetylation may have a central role in the quantitative regulation of Pepc gene expression.
- Gene
- Pepce0
- Outcome
- quantitative regulation of gene expressione2
- Qualifier
- upstream promoter acetylatione2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“photosynthetic phosphoenolpyruvate carboxylase (Pepc) promoter in maize”
e2“Our results suggest a central role of upstream promoter acetylation in the quantitative regulation of gene expression in this model gene”