Temporal gene regulation by p53 is associated with the rotational setting of its binding motifs in nucleosomes
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE157300 | GEO | 2021/03/30
REPOSITORIES: GEO
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Project description:The tumor suppressor protein p53 is a DNA-binding transcription factor (TF) that, once activated, coordinates the expression of thousands of target genes. Increased p53 binding to gene promoters occurs shortly after p53 activation. Intriguingly, gene transcription exhibits differential kinetics with some genes being induced early (early genes) and others being induced late (late genes). To understand pre-binding factors contributing to the temporal gene regulation by p53, we performed time-course RNA sequencing experiments in human colon cancer cell line HCT116 treated with fluorouracil to identify early and late genes. Published p53 ChIP fragments co-localized with the early or late genes were used to uncover p53 binding sites (BS). We demonstrate that the BS associated with early genes are clustered around gene starts with decreased nucleosome occupancy. DNA analysis shows that these BS are likely exposed on nucleosomal surface if wrapped into nucleosomes, thereby facilitating stable interactions with and fast induction by p53. By contrast, p53 BS associated with late genes are distributed uniformly across the genes with increased nucleosome occupancy. Predicted rotational settings of these BS show limited accessibility. We therefore propose a hypothetical model in which the BS are fully, partially or not accessible to p53 in the nucleosomal context. The partial accessibility of the BS allows subunits of a p53 tetramer to bind, but the resulting p53-DNA complex may not be stable enough to recruit cofactors, which leads to delayed induction. Our work highlights the importance of DNA conformations of p53 BS in gene expression dynamics.
| S-EPMC8098069 | biostudies-literature
Project description:Temporal gene regulation by p53 is associated with the rotational setting of its binding motifs in nucleosomes
| PRJNA660785 | ENA
Project description:Cisplatin and carboplatin are used successfully to treat various types of cancer. The drugs target the nucleosomes of cancer cells and form intrastrand DNA cross-links that are located in the major groove. We constructed two site-specifically modified nucleosomes containing defined intrastrand cis-{Pt(NH3)2}(2+) 1,3-d(GpTpG) cross-links. Histones from HeLa-S3 cancer cells were transferred onto synthetic DNA duplexes having nucleosome positioning sequences. The structures of these complexes were investigated by hydroxyl radical footprinting. Employing nucleosome positioning sequences allowed us to quantify the structural deviation induced by the cisplatin adduct. Our experiments demonstrate that a platinum cross-link locally overrides the rotational setting predefined in the nucleosome positioning sequence such that the lesion faces toward the histone core. Identical results were obtained for two DNA duplexes in which the sites of platination differed by approximately half a helical turn. Additionally, we determined that cisplatin unwinds nucleosomal DNA globally by approximately 24 degree. The intrastrand cis-{Pt(NH3)2}(2+) 1,3-d(GpTpG) cross-links are located in an area of the nucleosome that contains locally overwound DNA in undamaged reference nucleosomes. Because most nucleosome positions in vivo are defined by the intrinsic DNA sequence, the ability of cisplatin to influence the structure of these positioned nucleosomes may be of physiological relevance.
| S-EPMC2501106 | biostudies-literature
Project description:We constructed two site-specifically modified nucleosomes containing an intrastrand cis-{Pt(NH3)2}2+ 1,3-d(GpTpG) cross-link, similar to one formed by the anticancer drugs carboplatin and cisplatin on DNA, and investigated their structures by hydroxyl radical footprinting and exonuclease III digestion. Hydroxyl radical footprinting demonstrated that the presence of the platinum cross-link selects out a specific rotational setting of DNA on the histone octamer core in each of two reconstituted nucleosomes in which the platinum positions differ by half a DNA helical turn. The {Pt(NH3)2}2+ cross-link is situated in a structurally similar location, with the undamaged strand projecting outward, forcing the DNA to adopt opposite rotational settings in its wrapping around the histone octamer in the two nucleosomes. Enzymatic digestion by exonuclease III of the nucleosome substrates revealed that the platinum cross-link affects the translational positioning of the DNA, forcing it into an asymmetric arrangement with respect to the core histone proteins. We suggest that these phasing phenomena may be central to the recognition and processing of platinum-DNA adducts in cancer cells treated with these drugs and possibly may be common to other DNA damaging events.
| S-EPMC1194956 | biostudies-literature
Project description:5-Fluorouracil (5-FU) is one of the most common drugs used in chemotherapy because of its efficacy and stability. However, 5-FU has been known to work on only 10~15% of colon cancer patients. Therefore, the study of 5-FU sensitivity study is necessary to increase the survival of colon cancer patients. p53 is one of the factors that effect on drug sensitivity. Main function of p53 has been focused on transcription activity in cell death. Numerous drug related studies show that expression of wild-type p53 increases drug sensitivity in various cancer types through inducing apoptotic signaling pathways. Currently, it has been reported that p53 has both transcriptional and non-transcriptional activities in apoptosis. However, most studies about p53 non-transcriptional activities in apoptosis are mainly focused on p53 induced mitochondrial outer membrane permeabilization, triggering the release of pro-apoptotic factors. The chromatin structure and organization have strongly attracted because of their impacts in cellular phenotypes. Recent studies have been shown that changes in chromatin accessibility affect cell phenotypes for external stimuli. Since p53 plays an important role in drug sensitivity and 5-FU is an external stimulus for cancer cells, we hypothesized that p53 may effect on 5-FU sensitivity through different regulation of chromatin accessible regions between TP53-WT and TP53-KO cells. To determine the effect of p53 on chromatin accessibility modification associated with 5-FU sensitivity, ATAC-seq and RNA-seq were performed under 5-FU treatment on TP53-WT as drug sensitive and TP53-KO as drug resistant HCT116 cells. In this study, we found that 5-FU induces chromatin accessibility in both TP53-WT and TP53-KO cells. Moreover, our results show that 5-FU induced chromatin accessibility increases expression of apoptotic genes in TP53-WT HCT116 cells through p53 non-transcriptional activity in nucleus.
2021-02-10 | GSE157949 | GEO
Project description:5-Fluorouracil (5-FU) is one of the most common drugs used in chemotherapy because of its efficacy and stability. However, 5-FU has been known to work on only 10~15% of colon cancer patients. Therefore, the study of 5-FU sensitivity study is necessary to increase the survival of colon cancer patients. p53 is one of the factors that effect on drug sensitivity. Main function of p53 has been focused on transcription activity in cell death. Numerous drug related studies show that expression of wild-type p53 increases drug sensitivity in various cancer types through inducing apoptotic signaling pathways. Currently, it has been reported that p53 has both transcriptional and non-transcriptional activities in apoptosis. However, most studies about p53 non-transcriptional activities in apoptosis are mainly focused on p53 induced mitochondrial outer membrane permeabilization, triggering the release of pro-apoptotic factors. The chromatin structure and organization have strongly attracted because of their impacts in cellular phenotypes. Recent studies have been shown that changes in chromatin accessibility affect cell phenotypes for external stimuli. Since p53 plays an important role in drug sensitivity and 5-FU is an external stimulus for cancer cells, we hypothesized that p53 may effect on 5-FU sensitivity through different regulation of chromatin accessible regions between TP53-WT and TP53-KO cells. To determine the effect of p53 on chromatin accessibility modification associated with 5-FU sensitivity, ATAC-seq and RNA-seq were performed under 5-FU treatment on TP53-WT as drug sensitive and TP53-KO as drug resistant HCT116 cells. In this study, we found that 5-FU induces chromatin accessibility in both TP53-WT and TP53-KO cells. Moreover, our results show that 5-FU induced chromatin accessibility increases expression of apoptotic genes in TP53-WT HCT116 cells through p53 non-transcriptional activity in nucleus.
2021-02-10 | GSE157950 | GEO
Project description:The transcriptional profiles of the HCT116 parental cells following treatment with either 5-FU or SN38 for 24h were assessed. In addition, basal comparisons between HCT116 parental and HCT116 5-FU -resistant and HCT116 SN38-resistant cells were also assessed.
2009-03-30 | E-MEXP-1691 | biostudies-arrayexpress
Project description:HCT116 parental, HCT116 5-FU resistant and HCT116 oxaliplatin resistant cells have been transiently treated with with their respective drug (5-FU or oxaliplatin) for 0, 6 12 or 24h in 3 independent experiments.
2006-01-01 | E-MEXP-390 | biostudies-arrayexpress
Project description:HCT116 microarray done 12 hours after treatment with DMSO (control) or Nutlin
2014-05-15 | GSE53965 | GEO
Project description:The tumor suppressor protein p53 exhibits high affinity to the response elements regulating cell cycle arrest genes (CCA-sites), but relatively low affinity to the sites associated with apoptosis (Apo-sites). This in vivo tendency cannot be explained solely by the p53-DNA binding constants measured in vitro. Since p53 can bind nucleosomal DNA, we sought to understand if the two groups of p53 sites differ in their accessibility when embedded in nucleosomes. To this aim, we analyzed the sequence-dependent bending anisotropy of human genomic DNA containing p53 sites. For the 20 CCA-sites, we calculated rotational positioning patterns predicting that most of the sites are exposed on the nucleosomal surface. This is consistent with experimentally observed positioning of human nucleosomes. Remarkably, the sequence-dependent DNA anisotropy of both the p53 sites and flanking DNA work in concert producing strong positioning signals. By contrast, both the predicted and observed rotational settings of the 38 Apo-sites in nucleosomes suggest that many of these sites are buried inside, thus preventing immediate p53 recognition and delaying gene induction. The distinct chromatin organization of the CCA response elements appears to be one of the key factors facilitating p53-DNA binding and subsequent activation of genes associated with cell cycle arrest.
| S-EPMC3902933 | biostudies-literature