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.

The yeast alpha 2 protein can repress transcription by RNA polymerases I and II but not III

1993 ◽  
Vol 13 (7) ◽  
pp. 4029-4038
Author(s):  
B M Herschbach ◽  
A D Johnson
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Rna Polymerase Iii ◽  
Rna Polymerases ◽  
Rna Polymerase I ◽  
Cell Type ◽  
Yeast Saccharomyces Cerevisiae ◽  
Cell Type Specific ◽  
Polymerase I ◽  
Rna Polymerase Ii Transcription

The alpha 2 protein of the yeast Saccharomyces cerevisiae normally represses a set of cell-type-specific genes (the a-specific genes) that are transcribed by RNA polymerase II. In this study, we determined whether alpha 2 can affect transcription by other RNA polymerases. We find that alpha 2 can repress transcription by RNA polymerase I but not by RNA polymerase III. Additional experiments indicate that alpha 2 represses RNA polymerase I transcription through the same pathway that it uses to repress RNA polymerase II transcription. These results implicate conserved components of the transcription machinery as mediators of alpha 2 repression and exclude several alternate models.

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.

scholarly journals Stimulation in vitro of a heparin-resistant RNA polymerase I transcription complex

1981 ◽  
Vol 198 (1) ◽  
pp. 207-210 ◽  
Author(s):  
M K Haddox ◽  
D H Russell
Keyword(s):  
Rna Polymerase ◽  
Rna Synthesis ◽  
Initial Rate ◽  
Rna Polymerase I ◽  
Soluble Factor ◽  
Isolated Nuclei ◽  
Chromatin Template ◽  
Polymerase I

A soluble factor partially purified from calf liver increases transcription by RNA polymerase I in isolated nuclei. Addition of the factor to reactions which have reached a plateau owing to the inability to reinitiate on the endogenous chromatin template restores the initial rate of synthesis and stimulates an increased accumulation of RNA product. The RNA synthesis stimulated by factor addition is identical with that initiated in vivo in that it is resistant to heparin disruption.

scholarly journals Transcriptionally active RNA polymerases from Morris hepatomas and rat liver. Elucidation of the mechanism for the preferential increase in the tumour RNA polymerase I

1980 ◽  
Vol 190 (3) ◽  
pp. 781-789 ◽  
Author(s):  
B W Duceman ◽  
S T Jacob
Keyword(s):  
Rna Polymerase ◽  
Tumour Growth ◽  
Rna Polymerases ◽  
Rna Polymerase I ◽  
Product Analysis ◽  
Sephadex Column ◽  
Tissue Homogenates ◽  
Enzyme Pattern ◽  
Polymerase I

The amount and/or activity of DNA-dependent RNA polymerase I, Ii and III from resting liver, regenerating liver and a series of Morris hepatomas (5123D, 7800, 7777, 3924A) were determined after extraction of the enzymes from whole tissue homogenates and subsequent fractionation by DEAE-Sephadex column chromatography. When compared with resting liver, the tumours exhibited a characteristic enzyme pattern in which polymerase I, but not II, was increased. The increase in RNA polymerase I was proportional to the tumour growth rates. Alterations in polymerase III were confined to the most rapidly proliferating hepatomas. By contrast, all classes of RNA polymerase were found to be increased during liver regeneration. Relative to resting liver, the fastest growing tumour, 3924A, exhibited the highest activities and/or amounts of RNA polymerase I (8-fold) and III (5-fold) per g of tissue. These alterations in the tumour RNA polymerases were reflected in corresponding increases in the transcriptionally active (bound or chromatin-associated) enzyme population. The mechanisms underlying the augmented synthesis of RNA in vitro by bound polymerase I from hepatoma 3924A were elucidated by product analysis. The results indicated that, relative to liver RNA polymerase I, the tumour enzyme produced more nascent RNA chains and elongated these chains at a faster rate. The number of 3'-termini, as measured by incorporation into uridine, was higher in the hepatoma even under conditions which prevented re-initiation. suggesting increased amount of transcriptionally active RNA polymerase I in the tumour.

scholarly journals The yeast alpha 2 protein can repress transcription by RNA polymerases I and II but not III.

1993 ◽  
Vol 13 (7) ◽  
pp. 4029-4038 ◽  
Author(s):  
B M Herschbach ◽  
A D Johnson
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Rna Polymerase Iii ◽  
Rna Polymerases ◽  
Rna Polymerase I ◽  
Cell Type ◽  
Yeast Saccharomyces Cerevisiae ◽  
Cell Type Specific ◽  
Polymerase I ◽  
Rna Polymerase Ii Transcription

The alpha 2 protein of the yeast Saccharomyces cerevisiae normally represses a set of cell-type-specific genes (the a-specific genes) that are transcribed by RNA polymerase II. In this study, we determined whether alpha 2 can affect transcription by other RNA polymerases. We find that alpha 2 can repress transcription by RNA polymerase I but not by RNA polymerase III. Additional experiments indicate that alpha 2 represses RNA polymerase I transcription through the same pathway that it uses to repress RNA polymerase II transcription. These results implicate conserved components of the transcription machinery as mediators of alpha 2 repression and exclude several alternate models.

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 Mitotic repression of transcription in vitro.

1993 ◽  
Vol 120 (3) ◽  
pp. 613-624 ◽  
Author(s):  
P Hartl ◽  
J Gottesfeld ◽  
D J Forbes
Keyword(s):  
Protein Kinase ◽  
Rna Polymerase ◽  
Topoisomerase Ii ◽  
Chromatin Condensation ◽  
Rna Polymerase Iii ◽  
Protein Kinase Activity ◽  
Cdc2 Kinase ◽  
Polymerase Iii ◽  
Transcription In Vitro

A normal consequence of mitosis in eukaryotes is the repression of transcription. Using Xenopus egg extracts shifted to a mitotic state by the addition of purified cyclin, we have for the first time been able to reproduce a mitotic repression of transcription in vitro. Active RNA polymerase III transcription is observed in interphase extracts, but strongly repressed in extracts converted to mitosis. With the topoisomerase II inhibitor VM-26, we demonstrate that this mitotic repression of RNA polymerase III transcription does not require normal chromatin condensation. Similarly; in vitro mitotic repression of transcription does not require the presence of nucleosome structure or involve a general repressive chromatin-binding protein, as inhibition of chromatin formation with saturating amounts of non-specific DNA has no effect on repression. Instead, the mitotic repression of transcription appears to be due to phosphorylation of a component of the transcription machinery by a mitotic protein kinase, either cdc2 kinase and/or a kinase activated by it. Mitotic repression of RNA polymerase III transcription is observed both in complete mitotic cytosol and when a kinase-enriched mitotic fraction is added to a highly simplified 5S RNA transcription reaction. We present evidence that, upon depletion of cdc2 kinase, a secondary protein kinase activity remains and can mediate this in vitro mitotic repression of transcription.

Events during eucaryotic rRNA transcription initiation and elongation: conversion from the closed to the open promoter complex requires nucleotide substrates

1988 ◽  
Vol 8 (5) ◽  
pp. 1940-1946
Author(s):  
E Bateman ◽  
M R Paule
Keyword(s):  
Rna Polymerase ◽  
Transcription Initiation ◽  
Topological Analysis ◽  
Acanthamoeba Castellanii ◽  
Rna Polymerase I ◽  
Initiation Factor ◽  
Rrna Transcription ◽  
Promoter Complex ◽  
Polymerase I

Chemical footprinting and topological analysis were carried out on the Acanthamoeba castellanii rRNA transcription initiation factor (TIF) and RNA polymerase I complexes with DNA during transcription initiation and elongation. The results show that the binding of TIF and polymerase to the promoter does not alter the supercoiling of the DNA template and the template does not become sensitive to modification by diethylpyrocarbonate, which can identify melted DNA regions. Thus, in contrast to bacterial RNA polymerase, the eucaryotic RNA polymerase I-promoter complex is in a closed configuration preceding addition of nucleotides in vitro. Initiation and 3'-O-methyl CTP-limited translocation by RNA polymerase I results in separation of the polymerase-TIF footprints, leaving the TIF footprint unaltered. In contrast, initiation and translocation result in a significant change in the conformation of the polymerase-DNA complex, culminating in an unwound DNA region of at least 10 base pairs.

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