Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.7.6 (RNA polymerase)
34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

BTF2/TFIIH from human, delta from rat, and factor b from yeast are multisubunit basal transcription factors that have been shown to be closely associated with a protein kinase capable of phosphorylating the carboxyl-terminal domain of the large subunit of RNA polymerase II (Lu, H., Zawel, L., Fischer, L., Egly, J. M., and Reinberg, D. (1992) Nature 358, 641-645; Serizawa, H., Conaway, R. C., and Conaway, J. W. (1992) Proc. Natl. Acad. Sci. U.S.A. 89, 7476-7480; Feaver, W. J., Gileadi, O., and Kornberg, R. D. (1991) Cell 67, 1223-1230). We report here that a DNA-dependent ATPase and the previously characterized helicase (Schaeffer, L., Roy, R., Humbert, S., Moncollin, V., Vermeulen, W., Hoeijmakers, J., Chambon, P., and Egly, J. M. (1993) Science 260, 58-63) are both associated with BTF2 and reside with the p89 polypeptide subunit. The DNA requirement, the effect of Sarkosyl and staurosporine inhibitors, as well as nucleotide competition experiments, clearly distinguished ATPase/helicase from the carboxyl-terminal domain kinase. Using recombinant wild type or mutated p89/ERCC3 polypeptides and different forms of DNA template, we show the connection between ATPase and the helicase.
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PMID:The DNA-dependent ATPase activity associated with the class II basic transcription factor BTF2/TFIIH. 751 95

A 40 S multienzyme complex containing mtDNA polymerase was isolated from mitochondria of S. cerevisiae by density gradient centrifugation and by gel filtration chromatography. Besides DNA polymerase, RNA polymerase, primase, 3'-->5' exonuclease and an ATPase activities were found to be associated with it. The presence of some of these enzymes were confirmed by Western blot. This high molecular weight multienzyme complex containing DNA has most of the attributes of a putative replisome.
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PMID:Isolation and characterization of a multienzyme complex containing DNA replicative enzymes from mitochondria of S. cerevisiae. Multienzyme complex from yeast mitochondria. 756 53

In Escherichia coli the heat shock response is under the positive control of the sigma 32 transcription factor. Three of the heat shock proteins, DnaK, DnaI, and GrpE, play a central role in the negative autoregulation of this response at the transcriptional level. Recently, we have shown that the DnaK and DnaJ proteins can compete with RNA polymerase for binding to the sigma 32 transcription factor in the presence of ATP, by forming a stable DnaJ-sigma 32-DnaK protein complex. Here, we report that DnaJ protein can catalytically activate DnaK's ATPase activity. In addition, DnaJ can activate DnaK to bind to sigma 32 in an ATP-dependent reaction, forming a stable sigma 32-DnaK complex. Results obtained with two DnaJ mutants, a missense and a truncated version, suggest that the N-terminal portion of DnaJ, which is conserved in all family members, is essential for this activation reaction. The activated form of DnaK binds preferentially to sigma 32 versus the bacteriophage lambda P protein substrate.
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PMID:The DnaJ chaperone catalytically activates the DnaK chaperone to preferentially bind the sigma 32 heat shock transcriptional regulator. 760 76

NTRC is a prokaryotic enhancer-binding protein that activates transcription by sigma 54-holoenzyme. NTRC has an ATPase activity that is required for transcriptional activation, specifically for isomerization of closed complexes between sigma 54-holoenzyme and a promoter to open complexes. In the absence of ATP hydrolysis, there is known to be a kinetic barrier to open complex formation (i.e., the reaction proceeds so slowly that the polymerase synthesizes essentially no transcripts even from a supercoiled template). We show here that open complex formation is also thermodynamically unfavorable. In the absence of ATP hydrolysis the position of equilibrium between closed and open complexes favors the closed ones. Use of linear templates with a region of heteroduplex around the transcriptional start site--"preopened" templates--does not bypass the requirement for either NTRC or ATP hydrolysis, providing evidence that the rate-limiting step in open complex formation does not lie in DNA strand denaturation per se. These results are in contrast to recent findings regarding the ATP requirement for initiation of transcription by eukaryotic RNA polymerase II; in the latter case, the ATP requirement is circumvented by use of a supercoiled plasmid template or a preopened linear template.
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PMID:The bacterial enhancer-binding protein NTRC is a molecular machine: ATP hydrolysis is coupled to transcriptional activation. 764 82

The RAD25 gene of Saccharomyces cerevisiae is required for excision repair of ultraviolet-damaged DNA and, in addition, is essential for viability. RAD25 shares a high degree of homology with the human ERCC3/XPBC-encoded protein, and the yeast and human proteins resemble one another in containing the conserved ATPase/DNA helicase sequence motifs. To determine the nature of the essential role of RAD25, we have isolated a recessive temperature-sensitive conditional lethal mutation of the gene and have examined its effect on transcription. Upon shift to the nonpermissive temperature, the rad25 temperature-sensitive (ts) mutant stops growth rapidly and shows a large decrease in the synthesis of poly(A)+ RNA. Transcription of a large number of yeast genes, including HIS3, TRP3, STE2, MET19, RAD23, CDC9, and ACT1 is inhibited at the restrictive temperature in the rad25 ts mutant, and the galactose-inducible synthesis of GAL7 and GAL10 mRNAs is also severely affected by the loss of RAD25 activity. These findings implicate a general requirement of RAD25 in RNA polymerase II transcription.
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PMID:The Saccharomyces cerevisiae DNA repair gene RAD25 is required for transcription by RNA polymerase II. 769 49

The heat-shock 70 protein (Hsp70) chaperone family is very conserved and its prokaryotic homologue, the DnaK protein, is assumed to form one of the cellular systems for the prevention and restoration of heat-induced protein denaturation. By using anti-DnaK antibodies we purified the DnaK homologue heat-shock cognate protein (Hsc70) from calf thymus to apparent homogeneity. This protein was classified as an eukaryotic Hsc70, since (i) monoclonal antibodies against eukaryotic Hsc70 recognized it, (ii) its amino-terminal sequence showed strong homology to Hsp70s from eukaryotes and, (iii) it had an intrinsic weak ATPase activity that was stimulated by various peptide substrates. We show that this calf thymus Hsc70 protein protected calf thymus DNA polymerases alpha and epsilon as well as Escherichia coli DNA polymerase III and RNA polymerase from heat inactivation and could reactivate these heat-inactivated enzymes in an ATP-hydrolysis dependent manner, likely leading to the dissociation of aggregates formed during heat inactivation. In contrast to this, DnaK protein was exclusively able to protect and to reactivate the enzymes from E.coli but not from eukaryotic cells. Finally, the addition of calf thymus DnaJ co-chaperone homologue reduced the amount of Hsc70 required for reactivation at least 10-fold.
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PMID:Calf thymus Hsc70 protein protects and reactivates prokaryotic and eukaryotic enzymes. 779 40

The predicted amino acid sequence of the vaccinia virus gene A18R shows significant homology to the human ERCC3 gene product, which is a member of the DEXH subfamily of the DNA and RNA helicase superfamily II and which plays a role in both RNA polymerase II transcription and nucleotide excision repair of DNA. The vaccinia virus A18R gene product is expressed throughout infection and is encapsidated in virions. Vaccinia virions containing mutant A18R gene product are defective in early viral transcription in vitro, and infection with A18R mutant virus results in aberrant viral transcription late during infection. Thus we hypothesize that the vaccinia virus A18R gene product is a helicase that plays a role in viral transcription and possibly DNA repair. As a first test of this hypothesis, we have affinity purified an amino-terminal polyhistidine-tagged A18R protein and shown that it has DNA-dependent ATPase activity. The A18R ATPase activity is stimulated by both single-stranded and double-stranded DNA and by RNA.DNA hybrids, but not by either single-stranded or double-stranded RNA.
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PMID:The vaccinia virus A18R gene product is a DNA-dependent ATPase. 782 83

cDNA clone MS73 codes for an ATPase that is a regulatory subunit of the 26 S proteasome. Reverse transcriptase polymerase chain reaction analysis demonstrates that the expression of the gene dramatically increases in the pre-eclosion period. Western analyses show increases in other related. ATPases including MS73, MSS1, and mts2 but not TBP1. A similar increase in the 30-kDa subunit of the 20 S proteasome occurs. There are accompanying large changes in the peptidase activities of the 26 S proteasome. Relative to the 30-kDa subunit, there is no change in MSS1 and MS73, a 3-fold increase in mts2, and a 5-fold decline in TBP1. A large increase in the concentration of 26 S proteasomes together with extensive regulatory reprogramming may facilitate rapid muscular proteolysis.
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PMID:Developmental changes of the 26 S proteasome in abdominal intersegmental muscles of Manduca sexta during programmed cell death. 782 21

The enteric NtrC (NRI) protein has been the paradigm for a class of bacterial enhancer-binding proteins (EBPs) that activate transcription of RNA polymerase containing the sigma 54 factor. Activators in the NtrC class are characterized by essentially three properties: (i) they bind to sites distant from the promoters that they activate (> 100 bp upstream of the transcriptional start site), (ii) they contain a conserved nucleotide-binding fold and exhibit ATPase activity that is required for activation, and (iii) they activate the sigma 54 RNA polymerase. We have characterized the NtrC protein from a photosynthetic bacterium, Rhodobacter capsulatus, which represents a metabolically versatile group of bacteria found in aquatic environments. We have shown that the R. capsulatus NtrC protein (RcNtrC) binds to two tandem sites that are distant from promoters that it activates, nifA1 and nifA2. These tandem binding sites are shown to be important for RcNtrC-dependent nitrogen regulation in vivo. Moreover, the conserved nucleotide-binding fold of RcNtrC is required to activate nifA1 and nifA2 but is not required for DNA binding of RcNtrC to upstream activation sequences. However, nifA1 and nifA2 genes do not require the sigma 54 for activation and do not contain the highly conserved nucleotides that are present in all sigma 54-type, EBP-activated promoters. Thus, the NtrC from this photosynthetic bacterium represents a novel member of the class of bacterial EBPs. It is probable that this class of EBPs is more versatile in prokaryotes than previously envisioned.
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PMID:A new type of NtrC transcriptional activator. 792 86

Fifty-eight cDNA clones isolated from a library of transcripts exhibiting up regulation in tomato root giant cells induced by infection with the parasitic nematode Meloidogyne incognita were characterized. A survey of plant tissues identified 31 transcripts present in tissues other than root, including actively dividing and expanding tissues and mature leaf tissues. The identities of approximately 20% of the giant cell transcripts were inferred from DNA sequence data; they include sequences encoding a plasmalemma proton ATPase, a putative Myb-type transcription factor, and the largest subunit of RNA polymerase II.
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PMID:DNA sequence and expression analysis of root-knot nematode-elicited giant cell transcripts. 801 51


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