scholarly journals Atypical clinical presentation of a subset of patients with anti-RNA polymerase III - non-scleroderma cases associated with dominant RNA polymerase i reactivity and nucleolar staining

2011 ◽  
Vol 13 (4) ◽  
pp. R119 ◽  
Author(s):  
Angela Ceribelli ◽  
Malgorzata E Krzyszczak ◽  
Yi Li ◽  
Steven J Ross ◽  
Jason YF Chan ◽  
...  
1988 ◽  
Vol 8 (2) ◽  
pp. 1001-1005 ◽  
Author(s):  
J Tower ◽  
B Sollner-Webb

Extracts of cells that are down-regulated for transcription by RNA polymerase I and RNA polymerase III exhibit a reduced in vitro transcriptional capacity. We have recently demonstrated that the down-regulation of polymerase I transcription in extracts of cycloheximide-treated and stationary-phase cells results from a lack of an activated subform of RNA polymerase I which is essential for rDNA transcription. To examine whether polymerase III transcriptional down-regulation occurs by a similar mechanism, the polymerase III transcription factors were isolated and added singly and in pairs to control cell extracts and to extracts of cells that had reduced polymerase III transcriptional activity due to cycloheximide treatment or growth into stationary phase. These down-regulations result from a specific reduction in TFIIIB; TFIIIC and polymerase III activities remain relatively constant. Thus, although transcription by both polymerase III and polymerase I is substantially decreased in extracts of growth-arrested cells, this regulation is brought about by reduction of different kinds of activities: a component of the polymerase III stable transcription complex in the former case and the activated subform of RNA polymerase I in the latter.


1988 ◽  
Vol 8 (2) ◽  
pp. 1001-1005 ◽  
Author(s):  
J Tower ◽  
B Sollner-Webb

Extracts of cells that are down-regulated for transcription by RNA polymerase I and RNA polymerase III exhibit a reduced in vitro transcriptional capacity. We have recently demonstrated that the down-regulation of polymerase I transcription in extracts of cycloheximide-treated and stationary-phase cells results from a lack of an activated subform of RNA polymerase I which is essential for rDNA transcription. To examine whether polymerase III transcriptional down-regulation occurs by a similar mechanism, the polymerase III transcription factors were isolated and added singly and in pairs to control cell extracts and to extracts of cells that had reduced polymerase III transcriptional activity due to cycloheximide treatment or growth into stationary phase. These down-regulations result from a specific reduction in TFIIIB; TFIIIC and polymerase III activities remain relatively constant. Thus, although transcription by both polymerase III and polymerase I is substantially decreased in extracts of growth-arrested cells, this regulation is brought about by reduction of different kinds of activities: a component of the polymerase III stable transcription complex in the former case and the activated subform of RNA polymerase I in the latter.


2001 ◽  
Vol 21 (1) ◽  
pp. 189-195 ◽  
Author(s):  
Jean-François Briand ◽  
Francisco Navarro ◽  
Olivier Gadal ◽  
Pierre Thuriaux

ABSTRACT Temperature-sensitive RNA polymerase III (rpc160-112and rpc160-270) mutants were analyzed for the synthesis of tRNAs and rRNAs in vivo, using a double-isotopic-labeling technique in which cells are pulse-labeled with [33P]orthophosphate and coextracted with [3H]uracil-labeled wild-type cells. Individual RNA species were monitored by Northern blot hybridization or amplified by reverse transcription. These mutants impaired the synthesis of RNA polymerase III transcripts with little or no influence on mRNA synthesis but also largely turned off the formation of the 25S, 18S, and 5.8S mature rRNA species derived from the common 35S transcript produced by RNA polymerase I. In the rpc160-270mutant, this parallel inhibition of tRNA and rRNA synthesis also occurred at the permissive temperature (25°C) and correlated with an accumulation of 20S pre-rRNA. In the rpc160-112 mutant, inhibition of rRNA synthesis and the accumulation of 20S pre-rRNA were found only at 37°C. The steady-state rRNA/tRNA ratio of these mutants reflected their tRNA and rRNA synthesis pattern: therpc160-112 mutant had the threefold shortage in tRNA expected from its preferential defect in tRNA synthesis at 25°C, whereas rpc160-270 cells completely adjusted their rRNA/tRNA ratio down to a wild-type level, consistent with the tight coupling of tRNA and rRNA synthesis in vivo. Finally, an RNA polymerase I (rpa190-2) mutant grown at the permissive temperature had an enhanced level of pre-tRNA, suggesting the existence of a physiological coupling between rRNA synthesis and pre-tRNA processing.


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.


2009 ◽  
Vol 9 (2) ◽  
pp. 325-335 ◽  
Author(s):  
Elisa Cesarini ◽  
Francesca Romana Mariotti ◽  
Francesco Cioci ◽  
Giorgio Camilloni

ABSTRACT In Saccharomyces cerevisiae the repeated units of the ribosomal locus, transcribed by RNA polymerase I (Pol I), are interrupted by nontranscribed spacers (NTSs). These NTS regions are transcribed by RNA polymerase III to synthesize 5S RNA and by RNA polymerase II (Pol II) to synthesize, at low levels, noncoding RNAs (ncRNAs). While transcription of both RNA polymerase I and III is highly characterized, at the ribosomal DNA (rDNA) locus only a few studies have been performed on Pol II, whose repression correlates with the SIR2-dependent silencing. The involvement of both chromatin organization and Pol I transcription has been proposed, and peculiar chromatin structures might justify “ribosomal” Pol II silencing. Reporter genes inserted within the rDNA units have been employed for these studies. We studied, in the natural context, yeast mutants differing in Pol I transcription in order to find whether correlations exist between Pol I transcription and Pol II ncRNA production. Here, we demonstrate that silencing at the rDNA locus represses ncRNAs with a strength inversely proportional to Pol I transcription. Moreover, localized regions of histone hyperacetylation appear in cryptic promoter elements when Pol II is active and in the coding region when Pol I is functional; in addition, DNA topoisomerase I site-specific activity follows RNA polymerase I transcription. The repression of ncRNAs at the rDNA locus, in response to RNA polymerase I transcription, could represent a physiological circuit control whose mechanism involves modification of histone acetylation.


1993 ◽  
Vol 13 (7) ◽  
pp. 4029-4038
Author(s):  
B M Herschbach ◽  
A D Johnson

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.


2006 ◽  
Vol 54 (9) ◽  
pp. 3051-3056 ◽  
Author(s):  
Yoshioki Yamasaki ◽  
Minna Honkanen-Scott ◽  
Liza Hernandez ◽  
Keigo Ikeda ◽  
Tolga Barker ◽  
...  

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