Melafen stimulates RNA polymerase I activity but has no effect on plastid gene transcription in barley

2010 ◽  
Vol 431 (1) ◽  
pp. 82-86 ◽  
Author(s):  
V. V. Kusnetsov ◽  
A. K. Kravtsov ◽  
S. Yu. Selivankina ◽  
Ya. O. Zubo ◽  
N. K. Zubkova ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Gene Transcription ◽  
Rna Polymerase I ◽  
Plastid Gene ◽  
Polymerase I

scholarly journals Association of DNA topoisomerase I and RNA polymerase I: a possible role for topoisomerase I in ribosomal gene transcription

Chromosoma ◽  
1988 ◽  
Vol 96 (6) ◽  
pp. 411-416 ◽  
Author(s):  
Kathleen M. Rose ◽  
Jan Szopa ◽  
Fu-Sheng Han ◽  
Yung-Chi Cheng ◽  
Arndt Richter ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Gene Transcription ◽  
Topoisomerase I ◽  
Ribosomal Gene ◽  
Rna Polymerase I ◽  
Dna Topoisomerase I ◽  
Dna Topoisomerase ◽  
Polymerase I

scholarly journals Feedback regulation of vitamin D metabolism by 1,25-dihydroxycholecalciferol

1977 ◽  
Vol 164 (1) ◽  
pp. 83-89 ◽  
Author(s):  
K W Colston ◽  
I M A Evans ◽  
T C Spelsberg ◽  
I MacIntyre
Keyword(s):  
Vitamin D ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Gene Transcription ◽  
Subcutaneous Administration ◽  
Feedback Regulation ◽  
Rna Polymerase I ◽  
Hydroxylase Activity ◽  
Vitamin D Metabolism ◽  
Polymerase I

Many factors influence the production of 1,25(OH)2D3 (1,25-dihydroxycholecalciferol) by the kidney. One important factor seems to be feedback regulation by 1,25(OH)2D3 itself. Administration of 1,25(OH)2D3 to vitamin D-deficient chicks abolishes renal 25(OH)D3(25-hydroxycholecalciferol)1-hydroxylase activity and induces the appearance of 25(OH)D3 24-hydroxylase activity. It is likely that these effects are mediated via a nuclear effect, as they are prevented by pretreatment with actinomycin D and alpha-amanitin. Further, 1,25(OH)2D3 has a marked effect on gene transcription in the kidney cell, as assessed by measurement of RNA polymerase activities. RNA polymerase I and II activities are 80-90% inhibited by 12.5nmol of 1,25(OH)2D3 within 30min of subcutaneous administration, indicating an immediate and massive decrease in total gene transcription. By 4h RNA polymerase II activity has returned to control values, but RNA polymerase I activity is markedly enhanced. These results are consistent with the view that regulation of cholecalciferol metabolism in the kidney is associated with an effect of the active metabolite on the kidney nucleus.

Identification of two steps during Xenopus ribosomal gene transcription that are sensitive to protein phosphorylation

1994 ◽  
Vol 14 (3) ◽  
pp. 2011-2020
Author(s):  
P Labhart
Keyword(s):  
Protein Kinase ◽  
Rna Polymerase ◽  
Protein Phosphorylation ◽  
Gene Transcription ◽  
Okadaic Acid ◽  
Protein Phosphatase ◽  
Transcription Initiation ◽  
Ribosomal Gene ◽  
Rna Polymerase I ◽  
Polymerase I

Protein kinase(s) and protein phosphatase(s) present in a Xenopus S-100 transcription extract strongly influence promoter-dependent transcription by RNA polymerase I. The protein kinase inhibitor 6-dimethyl-aminopurine causes transcription to increase, while the protein phosphatase inhibitor okadaic acid causes transcription to decrease. Repression is also observed with inhibitor 2, and the addition of extra protein phosphatase 1 stimulates transcription, indicating that the endogenous phosphatase is a type 1 enzyme. Partial fractionation of the system, single-round transcription reactions, and kinetic experiments show that two different steps during ribosomal gene transcription are sensitive to protein phosphorylation: okadaic acid affects a step before or during transcription initiation, while 6-dimethylaminopurine stimulates a process "late" in the reaction, possibly reinitiation. The present results are a clear demonstration that transcription by RNA polymerase I can be regulated by protein phosphorylation.

scholarly journals Human Nopp140, Which Interacts with RNA Polymerase I: Implications for rRNA Gene Transcription and Nucleolar Structural Organization

1999 ◽  
Vol 19 (12) ◽  
pp. 8536-8546 ◽  
Author(s):  
Hung-Kai Chen ◽  
Chi-Yun Pai ◽  
Jing-Yi Huang ◽  
Ning-Hsing Yeh
Keyword(s):  
Amino Acids ◽  
Rna Polymerase ◽  
Gene Transcription ◽  
Ectopic Expression ◽  
Rna Polymerase I ◽  
Rrna Genes ◽  
Rrna Synthesis ◽  
Rrna Gene ◽  
Amino Terminal ◽  
Polymerase I

ABSTRACT Nopp140 is thought to shuttle between nucleolus and cytoplasm. However, the predominant nucleolar localization of Nopp140 homologues from different species suggests that Nopp140 is also involved in events occurring within the nucleolus. In this study, we demonstrated that the largest subunit of RNA polymerase I, RPA194, was coimmunoprecipitated with the human Nopp140 (hNopp140). Such an interaction is mediated through amino acids 204 to 382 of hNopp140. By double immunofluorescence, hNopp140 was colocalized with RNA polymerase I at the rDNA (rRNA genes) transcription active foci in the nucleolus. These results suggest that Nopp140 can interact with RNA polymerase I in vivo. Transfected cells expressing the amino-terminal half of hNopp140, hNopp140N382 (amino acids 1 to 382), displayed altered nucleoli with crescent-shaped structures. This phenotype is reminiscent of the segregated nucleoli induced by actinomycin D treatment, which is known to inhibit rRNA synthesis. Consistently, the hNopp140N382 protein mislocalized the endogenous RNA polymerase I and shut off cellular rRNA gene transcription as revealed by an in situ run-on assay. These dominant negative effects of the mutant hNopp140N382 suggest that Nopp140 plays an essential role in rDNA transcription. Interestingly, ectopic expression of hNopp140 to a very high level caused the formation of a transcriptionally inactive spherical structure occupying the entire nucleolar area which trapped the RNA polymerase I, fibrillarin, and hNopp140 but excluded the nucleolin. The mislocalizations of these nucleolar proteins after hNopp140 overexpression imply that Nopp140 may also play roles in maintenance of nucleolar integrity.

scholarly journals Identification of two steps during Xenopus ribosomal gene transcription that are sensitive to protein phosphorylation.

1994 ◽  
Vol 14 (3) ◽  
pp. 2011-2020 ◽  
Author(s):  
P Labhart
Keyword(s):  
Protein Kinase ◽  
Rna Polymerase ◽  
Protein Phosphorylation ◽  
Gene Transcription ◽  
Okadaic Acid ◽  
Protein Phosphatase ◽  
Transcription Initiation ◽  
Ribosomal Gene ◽  
Rna Polymerase I ◽  
Polymerase I

Protein kinase(s) and protein phosphatase(s) present in a Xenopus S-100 transcription extract strongly influence promoter-dependent transcription by RNA polymerase I. The protein kinase inhibitor 6-dimethyl-aminopurine causes transcription to increase, while the protein phosphatase inhibitor okadaic acid causes transcription to decrease. Repression is also observed with inhibitor 2, and the addition of extra protein phosphatase 1 stimulates transcription, indicating that the endogenous phosphatase is a type 1 enzyme. Partial fractionation of the system, single-round transcription reactions, and kinetic experiments show that two different steps during ribosomal gene transcription are sensitive to protein phosphorylation: okadaic acid affects a step before or during transcription initiation, while 6-dimethylaminopurine stimulates a process "late" in the reaction, possibly reinitiation. The present results are a clear demonstration that transcription by RNA polymerase I can be regulated by protein phosphorylation.

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