The Experts below are selected from a list of 66 Experts worldwide ranked by ideXlab platform
J W Conaway - One of the best experts on this subject based on the ideXlab platform.
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Emerging Roles of Ubiquitin in Transcription Regulation
Science, 2002Co-Authors: R C Conaway, Christopher S. Brower, J W ConawayAbstract:Ubiquitin is a small protein that was initially found to function as a tag that can be covalently attached to proteins to mark them for destruction by a multisubunit, adenosine 5′-triphosphate–dependent protease called the proteasome. Ubiquitin is now emerging as a key regulator of eukaryotic Messenger RNA Synthesis, a process that depends on the RNA synthetic enzyme RNA polymerase II and the transcription factors that control its activity. Ubiquitin controls Messenger RNA Synthesis not only by mechanisms involving ubiquitin-dependent destruction of transcription factors by the proteasome, but also by an intriguing collection of previously unknown and unanticipated mechanisms that appear to be independent of the proteasome.
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Assays for Investigating Transcription by RNA Polymerase IIin Vitro
Methods, 1997Co-Authors: Daniel Reines, J W Conaway, Arik Dvir, R C ConawayAbstract:Abstract With the availability of the general initiation factors (TFIIB, TFIID, TFIIE, TFIIF, and TFIIH), it is now possible to investigate aspects of the mechanism of eukaryotic Messenger RNA Synthesis in purified, reconstituted RNA polymerase II transcription systems. Rapid progress in these investigations has been spurred by use of a growing number of assays that are proving valuable not only for dissecting the molecular mechanisms of transcription initiation and elongation by RNA polymerase II, but also for identifying and purifying novel transcription factors that regulate polymerase activity. Here we describe a variety of these assays and discuss their utility in the analysis of transcription by RNA polymerase II.
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Biochemical Studies of Eukaryotic Messenger RNA Synthesis (AMGEN Award lecture)
FASEB Journal, 1997Co-Authors: R C Conaway, J W ConawayAbstract:Our laboratory has exploited a straightforward biochemical approach to identier and characterize components of the RNA polymerase II transcriptional machinery. Recently, these studies led to tile discovery of two novel cellular proteins, Elongin A and ELL, which stimulate elongation by RNA polymerase II by suppressing transient pausing by polymerase at many sites along the DNA. Elongin A contains an inducible elongation activation domain that is potently activated by the Elongin BC coinplex. The Elongin BC complex is a cellular target of the von ttippel-Lindau tumor suppressor gene product, which is capable of negatively regulating Elongin A transcriptional activity in vitro by binding the Elongin BC complex and preventing it front activating Elongin A. The human ELL gene on chromosome 19p13.1 undergoes frequent translocations with the trithoraxdike M LL gene on chromosome [ 1q23 in acute myeloid leukemia. The ELL protein contains two unusual overlapping functional domains that govern its interaction wieh RNA polymerase II and the teRNAry elongation colnplex. The MLL-I:;LL eranslocation results in disruption of one of these ELL functional domains.
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Transcription syndromes and the role of RNA polymerase II general transcription factors in human disease.
Journal of Clinical Investigation, 1996Co-Authors: Ali Shilatifard, J W Conaway, R C ConawayAbstract:Messenger RNA Synthesis is a major site for the regulation of gene expression. Eukaryotic Messenger RNA Synthesis is catalyzed by multisubunit RNA polymerase II (1–3) and proceeds via multiple stages, which are designated preinitiation, initiation, elongation, and termination and which have come to be referred to collectively as the transcription cycle (Fig. 1). The past decade was a watershed for biochemical studies of eukaryotic Messenger RNA Synthesis. A diverse collection of transcription factors and other nuclear proteins that govern the activity of RNA polymerase II during Messenger RNA Synthesis was identified and characterized, and unprecedented progress in several key research areas has provided a deeper understanding of the biochemical mechanisms underlying many aspects of eukaryotic transcriptional regulation. First, major breakthroughs in investigations of the structures of eukaryotic protein-coding genes and the role of chromatin in the regulation of their expression were achieved. Chromatin proteins, such as histones and HMG proteins, were found to play crucial roles in gene regulation by packaging genes into inactive or transcriptionally repressed configurations (4–9). Second, many DNA binding transactivators that interact specifically with upstream promoter elements and enhancer sequences located in the promoter-regulatory regions of genes were isolated, classified according to their structures, and found to regulate the expression of specific genes or gene families by controlling the rate of initiation (10) and, as shown more recently, the efficiency of elongation by RNA polymerase II (11–13). Third, chromatin remodeling proteins, such as the multisubunit SWI/SNF (14, 15) and NURF (16, 17) complexes, were discovered and found to play key roles in transcriptional activation by promoting conversion of regions of inactive chromatin into transcriptionally active, open chromatin, thereby allowing DNA binding transactivators and RNA polymerase II access to the promoter-regulatory regions of genes (4, 18–23). Fourth, coactivators, such as the SRB-containing mediator complex (2, 3, 24, 25), CREB binding protein (CBP) 1
R C Conaway - One of the best experts on this subject based on the ideXlab platform.
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Emerging Roles of Ubiquitin in Transcription Regulation
Science, 2002Co-Authors: R C Conaway, Christopher S. Brower, J W ConawayAbstract:Ubiquitin is a small protein that was initially found to function as a tag that can be covalently attached to proteins to mark them for destruction by a multisubunit, adenosine 5′-triphosphate–dependent protease called the proteasome. Ubiquitin is now emerging as a key regulator of eukaryotic Messenger RNA Synthesis, a process that depends on the RNA synthetic enzyme RNA polymerase II and the transcription factors that control its activity. Ubiquitin controls Messenger RNA Synthesis not only by mechanisms involving ubiquitin-dependent destruction of transcription factors by the proteasome, but also by an intriguing collection of previously unknown and unanticipated mechanisms that appear to be independent of the proteasome.
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Assays for Investigating Transcription by RNA Polymerase IIin Vitro
Methods, 1997Co-Authors: Daniel Reines, J W Conaway, Arik Dvir, R C ConawayAbstract:Abstract With the availability of the general initiation factors (TFIIB, TFIID, TFIIE, TFIIF, and TFIIH), it is now possible to investigate aspects of the mechanism of eukaryotic Messenger RNA Synthesis in purified, reconstituted RNA polymerase II transcription systems. Rapid progress in these investigations has been spurred by use of a growing number of assays that are proving valuable not only for dissecting the molecular mechanisms of transcription initiation and elongation by RNA polymerase II, but also for identifying and purifying novel transcription factors that regulate polymerase activity. Here we describe a variety of these assays and discuss their utility in the analysis of transcription by RNA polymerase II.
-
Biochemical Studies of Eukaryotic Messenger RNA Synthesis (AMGEN Award lecture)
FASEB Journal, 1997Co-Authors: R C Conaway, J W ConawayAbstract:Our laboratory has exploited a straightforward biochemical approach to identier and characterize components of the RNA polymerase II transcriptional machinery. Recently, these studies led to tile discovery of two novel cellular proteins, Elongin A and ELL, which stimulate elongation by RNA polymerase II by suppressing transient pausing by polymerase at many sites along the DNA. Elongin A contains an inducible elongation activation domain that is potently activated by the Elongin BC coinplex. The Elongin BC complex is a cellular target of the von ttippel-Lindau tumor suppressor gene product, which is capable of negatively regulating Elongin A transcriptional activity in vitro by binding the Elongin BC complex and preventing it front activating Elongin A. The human ELL gene on chromosome 19p13.1 undergoes frequent translocations with the trithoraxdike M LL gene on chromosome [ 1q23 in acute myeloid leukemia. The ELL protein contains two unusual overlapping functional domains that govern its interaction wieh RNA polymerase II and the teRNAry elongation colnplex. The MLL-I:;LL eranslocation results in disruption of one of these ELL functional domains.
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Transcription syndromes and the role of RNA polymerase II general transcription factors in human disease.
Journal of Clinical Investigation, 1996Co-Authors: Ali Shilatifard, J W Conaway, R C ConawayAbstract:Messenger RNA Synthesis is a major site for the regulation of gene expression. Eukaryotic Messenger RNA Synthesis is catalyzed by multisubunit RNA polymerase II (1–3) and proceeds via multiple stages, which are designated preinitiation, initiation, elongation, and termination and which have come to be referred to collectively as the transcription cycle (Fig. 1). The past decade was a watershed for biochemical studies of eukaryotic Messenger RNA Synthesis. A diverse collection of transcription factors and other nuclear proteins that govern the activity of RNA polymerase II during Messenger RNA Synthesis was identified and characterized, and unprecedented progress in several key research areas has provided a deeper understanding of the biochemical mechanisms underlying many aspects of eukaryotic transcriptional regulation. First, major breakthroughs in investigations of the structures of eukaryotic protein-coding genes and the role of chromatin in the regulation of their expression were achieved. Chromatin proteins, such as histones and HMG proteins, were found to play crucial roles in gene regulation by packaging genes into inactive or transcriptionally repressed configurations (4–9). Second, many DNA binding transactivators that interact specifically with upstream promoter elements and enhancer sequences located in the promoter-regulatory regions of genes were isolated, classified according to their structures, and found to regulate the expression of specific genes or gene families by controlling the rate of initiation (10) and, as shown more recently, the efficiency of elongation by RNA polymerase II (11–13). Third, chromatin remodeling proteins, such as the multisubunit SWI/SNF (14, 15) and NURF (16, 17) complexes, were discovered and found to play key roles in transcriptional activation by promoting conversion of regions of inactive chromatin into transcriptionally active, open chromatin, thereby allowing DNA binding transactivators and RNA polymerase II access to the promoter-regulatory regions of genes (4, 18–23). Fourth, coactivators, such as the SRB-containing mediator complex (2, 3, 24, 25), CREB binding protein (CBP) 1
David L Dunn - One of the best experts on this subject based on the ideXlab platform.
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anti lipopolysaccharide monoclonal antibodies inhibit macrophage tnf Messenger RNA Synthesis in vitro
Journal of Surgical Research, 1993Co-Authors: Richard J Battafarano, Randall S Burd, Carolyn S Cody, Todd A Kellogg, Christopher S Raymond, Craig A Ratz, David L DunnAbstract:Gram-negative bacterial lipopolysaccharide (LPS, endotoxin) directly stimulates macrophages to produce tumor necrosis factor (TNF). TNF, in turn, produces a constellation of adverse effects that includes hypotension, systemic acidosis, arterial hypoxemia, and death. Transcription of the TNF gene occurs within minutes of LPS stimulation and appears to be a critical control point in the Synthesis and secretion of TNF protein by macrophages. We hypothesized that murine monoclonal antibody (mAb) 8G9 directed against Escherichia coli 0111:B4 LPS would provide protective capacity against an E. coli 0111:B4 bacterial challenge in vivo and would concurrently inhibit LPS-induced Synthesis of TNF mRNA and secretion of TNF protein in vitro. E. coli 0111:B4 LPS was used to stimulate a macrophage-derived cell line (RAW 264.7) to produce TNF in the presence or absence of mAb 8G9. Media alone and LPS without 8G9 mAb served as controls against which the effect of 8G9 mAb was compared. Total cellular RNA was purified and analyzed by a Northern blotting technique utilizing a radiolabeled cDNA probe specific for TNF mRNA. TNF mRNA levels from each sample were quantitated by autoradiograph densitometry. Pretreatment with mAb 8G9 provided protective capacity against an intraperitoneal E. coli 0111:B4 bacterial challenge in vivo when compared with saline pretreatment alone (22% versus 90% mortality respectively, P < 0.05). Preincubation of LPS with mAb 8G9 resulted in a significant inhibition of LPS-induced TNF mRNA Synthesis (63 ± 20%, P < 0.01) and TNF protein secretion (88 ± 10%, P < 0.001) in vitro. We concluded that inhibition of LPS-induced TNF Synthesis and secretion by mAb 8G9 is a key mechanism by which mAb 8G9 provides protection during gram-negative bacterial sepsis.
Shelley Bhattacharya - One of the best experts on this subject based on the ideXlab platform.
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Inorganic mercury binding to fish oocyte plasma membrane induces steroidogenesis and translatable Messenger RNA Synthesis
Biometals, 1997Co-Authors: Shawli Mondal, Banibrata Mukhopadhyay, Shelley BhattacharyaAbstract:Both in vitro and in vivo HgCl treatment demonstrated a remarkably high rate of progesterone Synthesis accompanied by a low rate of conversion to 17β-estradiol in the oocyte of Channa punctatus. On depuration, however, there was a reversal of the steroidogenic scenario with a low progesterone and high estradiol level. The accumulation of progesterone was positively correlated with the significant increase in 3β-hydroxysteroid dehydrogenase activity in the Hg-treated fish. Thus, it was clear that at the early stage of intoxication Hg does play a role in the induction of 3β-hydroxysteroid dehydrogenase in the oocyte of fish at the spawning stage. The induction of this enzyme was found to be mediated by specific binding of Hg to the plasma membrane Na-K-ATPase (B: 14 nmoles mg protein; K 1.14 x 108 moles) and increase in the specific Messenger RNA translating 3β-hydroxysteroid dehydrogenase. It is concluded that inorganic mercury is able to initiate translatable Messenger RNA Synthesis in fish oocyte at a low degree of intoxication.
C P Miller - One of the best experts on this subject based on the ideXlab platform.
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differential regulation of rat insulin i and ii Messenger RNA Synthesis effects of fasting and cyproheptadine
Molecular Endocrinology, 1991Co-Authors: S J Giddings, L R Carnaghi, L J Fischer, C P MillerAbstract:Rats and mice retain a duplicated insulin (I) gene. Because the duplicated gene shares only incomplete homology with the ancestral insulin (II) gene it may be regulated differently. In the studies presented here we measured changes in abundance of these distinct insulin mRNAs and their precursors in response to fasting and fasting plus a single dose of cyproheptadine, two experimental manipulations that cause changes in the level of total insulin mRNA in rats. Both diminished rat insulin II mRNA to a greater extent than rat insulin I mRNA. Rat insulin II mRNA comprised 41% of the total insulin mRNA in 0 h controls and decreased to 33% of the total insulin mRNA after a 10-h fast. Insulin II mRNA decreased to 26% of the total insulin mRNA 10 h after treatment with cyproheptadine. To determine whether these manipulations had effects on insulin mRNA Synthesis, precursors for each of the two mRNAs were quantified. Fasting for 24 h had only small effects on insulin I mRNA precursor, but diminished rat insulin I...