Search results for "Chromatin ImmunoPrecipitation"
showing 10 items of 87 documents
Cellular Inhibitor of Apoptosis Protein-1 (cIAP1) Can Regulate E2F1 Transcription Factor-mediated Control of Cyclin Transcription
2011
International audience; The inhibitor of apoptosis protein cIAP1 (cellular inhibitor of apoptosis protein-1) is a potent regulator of the tumor necrosis factor (TNF) receptor family and NF-B signaling pathways in the cytoplasm. However, in some primary cells and tumor cell lines, cIAP1 is expressed in the nucleus, and its nuclear function remains poorly understood. Here, we show that the N-terminal part of cIAP1 directly interacts with the DNA binding domain of the E2F1 transcription factor. cIAP1 dramatically increases the transcriptional activity of E2F1 on synthetic and CCNE promoters. This function is not conserved for cIAP2 and XIAP, which are cytoplasmic proteins. Chromatin immunoprec…
The Transcription Factors TBX2 and TBX3 Interact with Human Papillomavirus 16 (HPV16) L2 and Repress the Long Control Region of HPVs
2013
ABSTRACT The minor capsid protein L2 of human papillomaviruses (HPVs) has multiple functions during the viral life cycle. Although L2 is required for effective invasion and morphogenesis, only a few cellular interaction partners are known so far. Using yeast two-hybrid screening, we identified the transcription factor TBX2 as a novel interaction partner of HPV type 16 (HPV16) L2. Coimmunoprecipitations and immunofluorescence analyses confirmed the L2-TBX2 interaction and revealed that L2 also interacts with TBX3, another member of the T-box family. Transcription of the early genes during HPV infection is under the control of an upstream enhancer and early promoter region, the long control r…
Mechanism of leptin expression in breast cancer cells: role of hypoxia-inducible factor-1α
2007
We reported previously that the obesity hormone leptin is overexpressed in breast cancer biopsies. Here, we investigated molecular mechanisms involved in this process, focusing on conditions that are associated with obesity, that is, hyperinsulinemia and induction of hypoxia. By using quantitative real-time PCR, immunofluorescent detection of proteins and enzyme-linked immunosorbent assays, we found that treatment of MCF-7 breast cancer cells with high doses of insulin or the hypoxia-mimetic agent CoCl2, or culturing the cells under hypoxic conditions significantly increased the expression of leptin mRNA and protein. Notably, the greatest leptin mRNA and protein expression were observed und…
Melatonin induces transcriptional regulation of Bim by FoxO3a in HepG2 cells
2012
Background: Melatonin induces apoptosis in many different cancer cell lines, including hepatocellular carcinoma cells. However, the responsible pathways have not been clearly elucidated. A member of the forkhead transcription factors' family, FoxO3a, has been implicated in the expression of the proapoptotic protein Bim (a Bcl-2-interacting mediator of cell death). In this study, we used human HepG2 liver cancer cells as an in vitro model to investigate whether melatonin treatment induces Bim through regulation by the transcription factor FoxO3a. Methods: Cytotoxicity of melatonin was compared in HepG2 hepatoblastoma cells and primary human hepatocytes. Proapoptotic Bim expression was analys…
The HMGA1 protoncogene frequently deregulated in cancer is a transcriptional target of E2F1
2011
Reactivation of the HMGA1 protoncogene is very frequent in human cancer, but still very little is known on the molecular mechanisms leading to this event. Prompted by the finding of putative E2F binding sites in the human HMGA1 promoter and by the frequent deregulation of the RB/E2F1 pathway in human carcinogenesis, we investigated whether E2F1 might contribute to the regulation of HMGA1 gene expression. Here we report that E2F1 induces HMGA1 by interacting with a 193bp region of the HMGA1 promoter containing an E2F binding site surrounded by three putative Sp1 binding sites. Both gain and loss of function experiments indicate that Sp1 functionally interacts with E2F1 to promote HMGA1 expre…
The repair of oxidized purines in the DNA of human lymphocytes requires an activation involving NF-YA-mediated upregulation of OGG1.
2014
8-Oxoguanine DNA glycosylase (OGG1), which initiates the repair of DNA purine modifications such as 8-oxo-7,8-dihydroguanine (8-oxoG), is often regarded as a house keeping protein ubiquitously active in mammalian cells. We have analysed the repair rates of oxidized purines generated by photosensitization in peripheral human lymphocytes and observed that the cells were virtually unable to remove these lesions (less than 10% removal within 24h). However, stimulation of the lymphocytes with phytohemagglutinin (PHA) strongly accelerated the repair so that ∼30% of the lesions were repaired within 4h. Within 24h following PHA stimulation and preceding the induction of cell proliferation, Western …
Sus1, a functional component of the SAGA histone acetylase complex and the nuclear pore-associated mRNA export machinery
2004
12 páginas, 7 figuras, 1 tabla. Material suplementario en: https://doi.org/10.1016/S0092-8674(03)01025-0. The SUS1 sequences have been deposited in GenBank with the accession number AY278445.
Dynamic remodeling of histone modifications in response to osmotic stress in Saccharomyces cerevisiae.
2014
Abstract Background Specific histone modifications play important roles in chromatin functions; i.e., activation or repression of gene transcription. This participation must occur as a dynamic process. Nevertheless, most of the histone modification maps reported to date provide only static pictures that link certain modifications with active or silenced states. This study, however, focuses on the global histone modification variation that occurs in response to the transcriptional reprogramming produced by a physiological perturbation in yeast. Results We did a genome-wide chromatin immunoprecipitation analysis for eight specific histone modifications before and after saline stress. The most…
The Pisum sativum psp54 gene requires ABI3 and a chromatin remodeller to switch from a poised to a transcriptionally active state
2011
Summary •Aspects of transcriptional regulation in plants, such as the order in which transcriptional factors and the preinitiation complex are assembled, are obscure because studies carried out under conditions in which native chromatin structure is preserved are still few in comparison with those carried out under other conditions. •In vivo chromatin immunoprecipitation (ChIP) experiments were used here to study the regulation of Pisum sativum psp54, which codes for the precursor of a chromatin-associated protein in dry seeds. •Antibodies against PsSNF5, a component of the SWI/SNF remodelling complex, and against the transcriptional factor Pisum sativum abscisic acid insensitive 3 (PsABI3)…
TAF-ChIP: An ultra-low input approach for genome wide chromatin immunoprecipitation assay
2018
Chromatin immunoprecipitation (ChIP) followed by next generation sequencing is an invaluable and powerful technique to understand transcriptional regulation. However, ChIP is currently limited by the requirement of large amount of starting material. This renders studying rare cell populations very challenging, or even impossible. Here, we present a tagmentation-assisted fragmentation ChIP (TAF-ChIP) and sequencing method to generate high-quality datasets from low cell numbers. The method relies on Tn5 transposon activity to fragment the chromatin that is immunoprecipitated, thus circumventing the need for sonication or MNAse digestion to fragment. Furthermore, Tn5 adds the sequencing adapto…