scholarly journals High concentration of RNA polymerase I is responsible for the high rate of nucleolar transcription

1980 ◽  
Vol 188 (2) ◽  
pp. 381-385 ◽  
Author(s):  
F L Yu
Keyword(s):  
Rna Polymerase ◽  
Rna Synthesis ◽  
Rna Polymerases ◽  
Rna Polymerase I ◽  
High Rate ◽  
Unit Weight ◽  
High Concentration ◽  
Steady State Condition ◽  
Polymerase I ◽  
Nucleolar Rna

When isolated rat liver nuclei and nucleoli are compared for RNA synthesis in vitro, the rate of nucleolar RNA synthesis is found to be more than 10 times higher. In order to understand this high rate of nucleolar transcription, DNA from both nuclear and nucleolar fractions was isolated and compared for the ability to direct RNA synthesis with homologous RNA polymerases. No difference between these two templates is evident. On the other hand, when the total nuclear and nucleolar RNA polymerases are isolated and compared on a per-unit-weight-of-DNA basis, it becomes clear that the nucleolus has a 10-fold higher RNA polymerase concentration than the nucleus. This result suggests that RNA polymerase I concentration rather than the nucleolar DNA template efficiency is responsible for the observed high rate of nucleolar transcription under the normal steady-state condition.

Phosphorylation of RNA polymerases: specific association of protein kinase NIl with RNA polymerase I

1983 ◽  
Vol 302 (1108) ◽  
pp. 135-142 ◽  
Keyword(s):  
Protein Kinase ◽  
Rna Polymerase ◽  
Rna Synthesis ◽  
Rna Polymerase Iii ◽  
Rna Polymerases ◽  
Rna Polymerase I ◽  
Liver Protein ◽  
Protein Kinase N ◽  
Polymerase I

The activities of the three DNA-dependent RNA polymerases from a rapidly growing rat tumour, Morris hepatoma 3924 A, and from rat liver were examined. The activity of RNA polymerase I was higher in the tumour than in the liver. The enhanced capacity for RNA synthesis was a result of a higher concentration of polymerase I in the tumour as well as of an activation of this enzyme vivo. The possibility that the high specific activity of the hepatoma polymerase I resulted from phosphorylation was investigated. Two major cyclic-AMP-independent nuclear casein kinases (NI and N il) were identified; the activity of protein kinase N il in the tumour was ten times that in liver. Protein kinase N il was capable of activating and phosphorylating RNA polymerase I in vitro . This kinase could also stimulate RNA polymerase II activity, although to a lesser extent than RNA polymerase I. RNA polymerase III was not affected by protein kinase NIL Protein kinase N il was tightly associated with polymerase I and was found even in purified preparations of the polymerase. Antibodies against both RNA polymerase I and protein kinase N il were present in sera of patients with certain rheumatic autoimmune diseases. These results imply that RNA polymerase I and protein kinase NIl are in close association in vivo as well as in vitro and that polymerase phosphorylation may regulate the rate of ribosomal RNA synthesis in the cell.

scholarly journals Selective inhibition by zinc of RNA synthesis initiation in the RNA polymerase I reaction

FEBS Letters ◽  
1979 ◽  
Vol 99 (1) ◽  
pp. 29-32 ◽  
Author(s):  
Yoshikuni Nagamine ◽  
Den'ichi Mizuno ◽  
Shunji Natori
Keyword(s):  
Rna Polymerase ◽  
Rna Synthesis ◽  
Selective Inhibition ◽  
Rna Polymerase I ◽  
Polymerase I

scholarly journals Deoxyribonucleic acid-dependent ribonucleic acid polymerases from murine spleen cells. Increased amounts of the nucleolar species in leukaemic tissue

1973 ◽  
Vol 133 (4) ◽  
pp. 797-804 ◽  
Author(s):  
Donner F. Babcock ◽  
Marvin A. Rich
Keyword(s):  
Rna Synthesis ◽  
Rna Polymerases ◽  
Infected Tissue ◽  
Leukaemia Virus ◽  
Bivalent Cations ◽  
Murine Spleen ◽  
Insoluble Product ◽  
Polymerase I ◽  
Dna Template ◽  
Nucleolar Rna

1. In the spleens of infected mice, the Friend leukaemia virus induces a sharp increase in the ability of subsequently isolated nuclei to incorporate exogenous UTP into an acid-insoluble product. Inhibitor studies indicate that the incremental RNA synthesis proceeds from a DNA template and that both nucleolar and nucleoplasmic activities are involved. 2. The partially purified DNA-dependent RNA polymerases from control and virus-infected tissue are indistinguishable with respect to chromatographic mobility, dependence on bivalent cations, ionic strength, pH and their susceptibility to α-amanitin. The RNA polymerases of the murine spleen resemble the enzymes of other mammalian tissue in these properties. 3. A comparison of the amount of polymerase solubilized from normal and infected tissue correlates with the activity observed in assays of the respective nuclei. These experiments indicated that the increase in nucleolar RNA synthesis after infection is mediated by increased extractable polymerase I activity whereas the change in nucleoplasmic RNA synthesis results from an alteration of chromatin or a chromatin-associated factor.

Inactivation of rat liver RNA polymerases I and II and yeast RNA polymerase I by pyridoxal 5'-phosphate. Evidence for the participation of lysyl residues at the active site

Biochemistry ◽  
1975 ◽  
Vol 14 (22) ◽  
pp. 4907-4911 ◽  
Author(s):  
Joseph Martial ◽  
Josefina Zaldivar ◽  
Paulina Bull ◽  
Alejandro Venegas ◽  
Pablo Valenzuela
Keyword(s):  
Rna Polymerase ◽  
Rat Liver ◽  
Active Site ◽  
Rna Polymerases ◽  
Rna Polymerase I ◽  
Polymerase I

scholarly journals Targeting RNA Polymerase I with an Oral Small Molecule CX-5461 Inhibits Ribosomal RNA Synthesis and Solid Tumor Growth

2010 ◽  
Vol 71 (4) ◽  
pp. 1418-1430 ◽  
Author(s):  
Denis Drygin ◽  
Amy Lin ◽  
Josh Bliesath ◽  
Caroline B. Ho ◽  
Sean E. O'Brien ◽  
...  
Keyword(s):  
Tumor Growth ◽  
Rna Polymerase ◽  
Small Molecule ◽  
Ribosomal Rna ◽  
Solid Tumor ◽  
Rna Synthesis ◽  
Rna Polymerase I ◽  
Solid Tumor Growth ◽  
Polymerase I

scholarly journals Histone Acetyltransferase and Protein Kinase Activities Copurify with a Putative Xenopus RNA Polymerase I Holoenzyme Self-Sufficient for Promoter-Dependent Transcription

1999 ◽  
Vol 19 (1) ◽  
pp. 796-806 ◽  
Author(s):  
Annie-Claude Albert ◽  
Michael Denton ◽  
Milko Kermekchiev ◽  
Craig S. Pikaard
Keyword(s):  
Rna Polymerase ◽  
Histone Acetyltransferase ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Large Mass ◽  
Rna Polymerases ◽  
Rna Polymerase I ◽  
Pol I ◽  
Coomassie Blue ◽  
Polymerase I

ABSTRACT Mounting evidence suggests that eukaryotic RNA polymerases preassociate with multiple transcription factors in the absence of DNA, forming RNA polymerase holoenzyme complexes. We have purified an apparent RNA polymerase I (Pol I) holoenzyme from Xenopus laevis cells by sequential chromatography on five columns: DEAE-Sepharose, Biorex 70, Sephacryl S300, Mono Q, and DNA-cellulose. Single fractions from every column programmed accurate promoter-dependent transcription. Upon gel filtration chromatography, the Pol I holoenzyme elutes at a position overlapping the peak of Blue Dextran, suggesting a molecular mass in the range of ∼2 MDa. Consistent with its large mass, Coomassie blue-stained sodium dodecyl sulfate-polyacrylamide gels reveal approximately 55 proteins in fractions purified to near homogeneity. Western blotting shows that TATA-binding protein precisely copurifies with holoenzyme activity, whereas the abundant Pol I transactivator upstream binding factor does not. Also copurifying with the holoenzyme are casein kinase II and a histone acetyltransferase activity with a substrate preference for histone H3. These results extend to Pol I the suggestion that signal transduction and chromatin-modifying activities are associated with eukaryotic RNA polymerases.

Sign in / Sign up

Export Citation Format

Share Document