Search results for "Enhancer"

Functional characterization of the sea urchin sns chromatin insulator in erythroid cells.

2005

Abstract Chromatin insulators are regulatory elements that determine domains of genetic functions. We have previously described the characterization of a 265 bp insulator element, termed sns, localized at the 3′ end of the early histone H2A gene of the sea urchin Paracentrotus lividus. This sequence contains three cis-acting elements (Box A, Box B, and Box C + T) all needed for the enhancer-blocking activity in both sea urchin and human cells. The goal of this study was to further characterize the sea urchin sns insulator in the erythroid environment. We employed colony assays in human (K562) and mouse (MEL) erythroid cell lines. We tested the capability of sns to interfere with the communi…

Procollagen C-proteinase Enhancer Stimulates Procollagen Processing by Binding to the C-propeptide Region Only*

2011

Background: Procollagen C-proteinase enhancer-1 (PCPE-1) is an extracellular glycoprotein that increases activity of certain zinc metalloproteinases involved in tissue development and repair. Results: PCPE-1 binds uniquely to the C-propeptide region of the procollagen molecule. Conclusion: PCPE-1 enhances proteolysis by binding solely to the procollagen C-propeptides. Significance: These data may lead to future applications in the development of antifibrotic therapies.

Context-dependent Pax-5 repression of a PU.1/NF-κB regulated reporter gene in B lineage cells

2001

Enhancers located in the 3' end of the locus in part regulate immunoglobulin heavy chain (IgH) gene expression. One of these enhancers, HS 1,2, is developmentally regulated by DNA binding proteins like NF-kappaB, Pax-5 and the protein complex NF-alphaP in B lineage cells. Here we report that NF-alphaP is the ets protein PU.1. A glutathione-S-transferase (GST)-pulldown assay demonstrated that PU.1 can physically interact with NF-kappaB in solution. Experiments in COS cells showed that PU.1 and NF-kappaB (p50/c-Rel) can activate transcription of an enhancer linked reporter gene. The paired domain protein Pax-5 has previously been shown to repress enhancer-dependent transcription. Additional c…

The Sea Urchin sns Insulator Blocks CMV Enhancer following Integration in Human Cells

2001

Insulators are a new class of genetic elements that attenuate enhancer function directionally. Previously, we characterized in sea urchin a 265-bp-long insulator, termed sns. To test insulator activity following stable integration in human cells, we placed sns between the CMV enhancer and a tk promoter up-stream of a GFP transgene of plasmid or retroviral vectors. In contrast to controls, cells transfected or transduced with insulated constructs displayed a barely detectable fluorescence. Southern blot and PCR ruled out vector rearrangement following integration into host DNA; RNase protection confirmed the enhancer blocking activity. Finally, we demonstrate that two cis-acting sequences, p…

Functional characterization of the enhancer blocking element of the sea urchin early histone gene cluster reveals insulator properties and three esse…

2000

Insulator elements can be functionally identified by their ability to shield promoters from regulators in a position-dependent manner or their ability to protect adjacent transgenes from position effects. We have previously reported the identification of a 265 bp sns DNA fragment at the 3' end of the sea urchin H2A early histone gene that blocked expression of a reporter gene in transgenic embryos when placed between the enhancer and the promoter. Here we show that sns interferes with enhancer-promoter interaction in a directional manner. When sns is placed between the H2A modulator and the inducible tet operator, the modulator is barred from interaction with the basal promoter. However, th…

Chromatin structure of the Arabidopsis thaliana Adh promoter: analysis of nucleosome positioning

1997

Abstract The chromatin structure of the promoter and proximal 5′ transcribed region of the Arabidopsis thaliana Adh gene has been studied in three experimental models: whole plants under aerobic conditions in which the gene is repressed, whole plants under flooding-induced anaerobiosis, in which the expression of the gene occurs in some plant tissues and yeast cells in which the Arabidopsis Adh DNA had been cloned but is not expressed at all. Experiments of indirect end labelling after DNase I and micrococcal nuclease digestion of nuclei allowed us to conclude that no positioned nucleosomes exist in plant nuclei on the proximal region of the promoter (up to −350), probably due to the presen…

Intravitreal dexamethasone as an enhancer for the anti-VEGF treatment in neovascular ARMD: recovering an old ally

2010

THAP11 and HP1BP3 proteins are component of the HB-2.8 enhancer-blocker located in the human c-MYC chromatin domain.

2011

Generation of homozygosity and genome fixation in pea (Pisum sativum L.)

2013

Pea cultivars are nearly homozygous and thus homogeneous when they are released. The traditional method of selfing is slow and inefficient, taking up to ten generations of inbreeding following a cross to achieve a high level of homozygosity. Current single-seed-descent (SSD) methodologies enable a maximum of three generations per year to be developed in pea. Doubled haploidy and an in vitro based modified SSD technology have been utilised in many important crops for the rapid achievement of homozygosity, and thus acceleration of the breeding process. In pea, due to the lack of robust protocols, none of these technologies is routinely used in a breeding program. The aim of this study was to …

EZH2 mutations are frequent and represent an early event in follicular lymphoma

2013

Gain of function mutations in the H3K27 methyltransferase EZH2 represent a promising therapeutic target in germinal center lymphomas. In this study, we assessed the frequency and distribution of EZH2 mutations in a large cohort of patients with follicular lymphoma (FL) (n = 366) and performed a longitudinal analysis of mutation during the disease progression from FL to transformed FL (tFL) (n = 33). Mutations were detected at 3 recurrent mutation hot spots (Y646, A682, and A692) in 27% of FL cases with variant allele frequencies (VAF) ranging from 2% to 61%. By comparing VAF of EZH2 with other mutation targets (CREBBP, MLL2, TNFRSF14, and MEF2B), we were able to distinguish patients harbori…