Search results for " transcription"
showing 10 items of 810 documents
TFIIH Operates through an Expanded Proximal Promoter To Fine-Tune c-myc Expression
2004
A continuous stream of activating and repressing signals is processed by the transcription complex paused at the promoter of the c-myc proto-oncogene. The general transcription factor IIH (TFIIH) is held at promoters prior to promoter escape and so is well situated to channel the input of activators and repressors to modulate c-myc expression. We have compared cells expressing only a mutated p89 (xeroderma pigmentosum complementation group B [XPB]), the largest TFIIH subunit, with the same cells functionally complemented with the wild-type protein (XPB/wt-p89). Here, we show structural, compositional, and functional differences in transcription complexes between XPB and XPB/wt-89 cells at t…
Chromatin remodelling factor Mll1 is essential for neurogenesis from postnatal neural stem cells
2009
Epigenetic mechanisms that maintain neurogenesis throughout adult life remain poorly understood(1). Trithorax group (trxG) and Polycomb group (PcG) gene products are part of an evolutionarily conserved chromatin remodelling system that activate or silence gene expression, respectively(2). Although PcG member Bmi1 has been shown to be required for postnatal neural stem cell self-renewal(3,4), the role of trxG genes remains unknown. Here we show that the trxG member Mll1 (mixed-lineage leukaemia 1) is required for neurogenesis in the mouse postnatal brain. Mll1-deficient subventricular zone neural stem cells survive, proliferate and efficiently differentiate into glial lineages; however, neur…
The Sea Urchin sns5 Insulator Protects Retroviral Vectors From Chromosomal Position Effects by Maintaining Active Chromatin Structure
2009
Silencing and position-effect (PE) variegation (PEV), which is due to integration of viral vectors in heterochromatin regions, are considered significant obstacles to obtaining a consistent level of transgene expression in gene therapy. The inclusion of chromatin insulators into vectors has been proposed to counteract this position-dependent variegation of transgene expression. Here, we show that the sea urchin chromatin insulator, sns5, protects a recombinant gamma-retroviral vector from the negative influence of chromatin in erythroid milieu. This element increases the probability of vector expression at different chromosomal integration sites, which reduces both silencing and PEV. By chr…
p53-Mediated downregulation of H ferritin promoter transcriptional efficiency via NF-Y.
2008
The tumor suppressor protein p53 triggers many of the cellular responses to DNA damage by regulating the transcription of a series of downstream target genes. p53 acts on the promoter of the target genes by interacting with the trimeric transcription factor NF-Y. H ferritin promoter activity is tightly dependent on a multiprotein complex called Bbf; on this complex NF-Y plays a major role. The aim of this work was to study the modulation of H ferritin expression levels by p53. CAT reporter assays indicate that: (i) p53 overexpression strongly downregulates the transcriptional efficiency driven by an H ferritin promoter construct containing only the NF-Y recognition sequence and that the phe…
Dissection of the elements of osmotic stress response transcription factor Hot1 involved in the interaction with MAPK Hog1 and in the activation of t…
2013
Abstract The response to hyperosmotic stress is mediated by the HOG pathway. The MAP kinase Hog1 activates several transcription factors, regulates chromatin-modifying enzymes and, through its interaction with RNA polymerase II, it directs this enzyme to osmotic stress-controlled genes. For such targeting, this kinase requires the interaction with transcription factors Hot1 and Sko1. However, phosphorylation of these proteins by Hog1 is not required for their functionality. In this study, we aim to identify the Hot1 elements involved in Hog1-binding and in the activation of transcription. Two-hybrid experiments demonstrated that the Hot1 sequence between amino acids 340 and 534 and the CD e…
The Saccharomyces cerevisiae Hot1p regulated gene YHR087W (HGI1) has a role in translation upon high glucose concentration stress.
2012
Abstract Background While growing in natural environments yeasts can be affected by osmotic stress provoked by high glucose concentrations. The response to this adverse condition requires the HOG pathway and involves transcriptional and posttranscriptional mechanisms initiated by the phosphorylation of this protein, its translocation to the nucleus and activation of transcription factors. One of the genes induced to respond to this injury is YHR087W. It encodes for a protein structurally similar to the N-terminal region of human SBDS whose expression is also induced under other forms of stress and whose deletion determines growth defects at high glucose concentrations. Results In this work …
Maternal Oct-4 is a potential key regulator of the developmental competence of mouse oocytes
2008
Abstract Background The maternal contribution of transcripts and proteins supplied to the zygote is crucial for the progression from a gametic to an embryonic control of preimplantation development. Here we compared the transcriptional profiles of two types of mouse MII oocytes, one which is developmentally competent (MIISN oocyte), the other that ceases development at the 2-cell stage (MIINSN oocyte), with the aim of identifying genes and gene expression networks whose misregulated expression would contribute to a reduced developmental competence. Results We report that: 1) the transcription factor Oct-4 is absent in MIINSN oocytes, accounting for 2) the down-regulation of Stella, a matern…
Inhibition of activated STAT5 in Bcr/Abl expressing leukemia cells with new pimozide derivatives.
2014
STATs are transcription factors acting as intracellular signaling after stimulation with cytokines, growth factors and hormones. STAT5 is also constitutively active in many forms of cancers, including chronic myelogenous leukemia, acute lymphoblastic leukemia and Hodgkin's lymphoma. Recently, literature reported that the neuroleptic drug pimozide inhibits STAT5 phosphorylation inducing apoptosis in CML cells. We undertook an investigation from pimozide structure, obtaining simple derivatives with cytotoxic and STAT5-inhibitory activity, two of them markedly more potent than pimozide.
NFAT transcription factors in control of peripheral T cell tolerance.
2006
The Ca++-regulated calcineurin/NFAT cascade is one of the crucial signalling pathways that controls adaptive immunity. However, a number of novel experimental data suggest that, in addition to their role in T cell activation, NFATc transcription factors play also a decisive role in the generation of peripheral tolerance against self-antigens. This function of NFATc factors is mediated by controlling activation-induced cell death and clonal anergy of T helper cells and the activity of regulatory T cells. The multi-functional role of NFATc proteins characterize these transcription factors as key regulators of immunological tolerance and, if dysregulated, of development of autoimmune diseases.
MultiROMs and Online Applications Used for Teaching Phonetics in a Secondary School: A Critical Review
2012
The aim of the article is to evaluate the quality of the materials used to teach pronunciation in a Polish secondary school. Although the analysis covers all kinds of aids available for teachers, including a coursebook accompanied by a CD, the authors focus mainly on MultiROMs and online resources connected with a given book. The findings allow the authors to conclude which coursebook sets seem to be most effective in shaping students’ pronunciation and which exercises are most helpful, taking into consideration the level of students’ English. Additionally, the authors’ idea was to check whether these books take into consideration the aspects of pronunciation which prove to be especially di…