scholarly journals Polymerase III transcription factor B activity is reduced in extracts of growth-restricted cells.

1988 ◽  
Vol 8 (2) ◽  
pp. 1001-1005 ◽  
Author(s):  
J Tower ◽  
B Sollner-Webb
Keyword(s):  
Rna Polymerase ◽  
Stationary Phase ◽  
Rna Polymerase Iii ◽  
Control Cell ◽  
Rna Polymerase I ◽  
Rdna Transcription ◽  
Down Regulation ◽  
Cell Extracts ◽  
Polymerase Iii ◽  
Polymerase I

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.

Polymerase III transcription factor B activity is reduced in extracts of growth-restricted cells

1988 ◽  
Vol 8 (2) ◽  
pp. 1001-1005 ◽  
Author(s):  
J Tower ◽  
B Sollner-Webb
Keyword(s):  
Rna Polymerase ◽  
Stationary Phase ◽  
Rna Polymerase Iii ◽  
Control Cell ◽  
Rna Polymerase I ◽  
Rdna Transcription ◽  
Down Regulation ◽  
Cell Extracts ◽  
Polymerase Iii ◽  
Polymerase I

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.

scholarly journals Species-specific rDNA transcription is due to promoter-specific binding factors.

1984 ◽  
Vol 4 (2) ◽  
pp. 221-227 ◽  
Author(s):  
R Miesfeld ◽  
N Arnheim
Keyword(s):  
Rna Polymerase ◽  
Transcriptional Control ◽  
Specific Binding ◽  
Rna Polymerase I ◽  
Rdna Transcription ◽  
Nucleolar Dominance ◽  
Cell Extracts ◽  
Species Specific ◽  
Polymerase I

RNA polymerase I transcription factors were purified from HeLa and mouse L cell extracts by phosphocellulose chromatography. Three fractions from each species were found to be required for transcription. One of these fractions, virtually devoid of RNA polymerase I activity, was found to form a stable preinitiation complex with small DNA fragments containing promoter sequences from the homologous but not the heterologous species. These species-specific DNA-binding factors can explain nucleolar dominance in vivo in mouse-human hybrid somatic cells and species specificity in cell-free, RNA polymerase I-dependent transcription systems. The evolution of species-specific transcriptional control signals may be the natural outcome of a special relationship that exists between the RNA polymerase I transcription machinery and the multigene family coding for rRNA.

The absence of a human-specific ribosomal DNA transcription factor leads to nucleolar dominance in mouse greater than human hybrid cells

1984 ◽  
Vol 4 (7) ◽  
pp. 1306-1312
Author(s):  
R Miesfeld ◽  
B Sollner-Webb ◽  
C Croce ◽  
N Arnheim
Keyword(s):  
Transcription Factor ◽  
Rna Polymerase ◽  
Hybrid Cell ◽  
Rna Polymerase I ◽  
Hybrid Cells ◽  
Rdna Transcription ◽  
Nucleolar Dominance ◽  
Cell Extracts ◽  
Polymerase I ◽  
Human Specific

The basis for nucleolar dominance in mouse-human cell hybrids which contained all of the mouse chromosomes but an incomplete set of human chromosomes (M greater than H) was examined at the molecular level. S1 mapping data showed that these cells had the expected levels of steady-state rRNA transcribed from mouse ribosomal gene (rDNA) transcription units but undetectable levels of rRNA derived from the human rDNA transcription templates that are also present. RNA polymerase I-dependent, cell-free transcription extracts were made from three hybrid lines and were found to be capable of transcribing cloned rDNA templates of mouse but not human origin. Partially purified human factors required for rDNA transcription in vitro were added to the M greater than H extracts. One fraction with almost no RNA polymerase I activity conferred on these hybrid cell extracts the ability to transcribe a human rDNA template. These rescue experiments suggested that this required human-specific rDNA transcription factor(s) was effectively absent from the lines we examined and could account for nucleolar dominance in M greater than H hybrid cells.

scholarly journals Cross Talk between tRNA and rRNA Synthesis inSaccharomyces cerevisiae

2001 ◽  
Vol 21 (1) ◽  
pp. 189-195 ◽  
Author(s):  
Jean-François Briand ◽  
Francisco Navarro ◽  
Olivier Gadal ◽  
Pierre Thuriaux
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Iii ◽  
Rna Polymerase I ◽  
Rrna Synthesis ◽  
Northern Blot Hybridization ◽  
Permissive Temperature ◽  
Wild Type ◽  
Polymerase Iii ◽  
Polymerase I

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.

scholarly journals The absence of a human-specific ribosomal DNA transcription factor leads to nucleolar dominance in mouse greater than human hybrid cells.

1984 ◽  
Vol 4 (7) ◽  
pp. 1306-1312 ◽  
Author(s):  
R Miesfeld ◽  
B Sollner-Webb ◽  
C Croce ◽  
N Arnheim
Keyword(s):  
Transcription Factor ◽  
Rna Polymerase ◽  
Hybrid Cell ◽  
Rna Polymerase I ◽  
Hybrid Cells ◽  
Rdna Transcription ◽  
Nucleolar Dominance ◽  
Cell Extracts ◽  
Polymerase I ◽  
Human Specific

The basis for nucleolar dominance in mouse-human cell hybrids which contained all of the mouse chromosomes but an incomplete set of human chromosomes (M greater than H) was examined at the molecular level. S1 mapping data showed that these cells had the expected levels of steady-state rRNA transcribed from mouse ribosomal gene (rDNA) transcription units but undetectable levels of rRNA derived from the human rDNA transcription templates that are also present. RNA polymerase I-dependent, cell-free transcription extracts were made from three hybrid lines and were found to be capable of transcribing cloned rDNA templates of mouse but not human origin. Partially purified human factors required for rDNA transcription in vitro were added to the M greater than H extracts. One fraction with almost no RNA polymerase I activity conferred on these hybrid cell extracts the ability to transcribe a human rDNA template. These rescue experiments suggested that this required human-specific rDNA transcription factor(s) was effectively absent from the lines we examined and could account for nucleolar dominance in M greater than H hybrid cells.

Species-specific rDNA transcription is due to promoter-specific binding factors

1984 ◽  
Vol 4 (2) ◽  
pp. 221-227
Author(s):  
R Miesfeld ◽  
N Arnheim
Keyword(s):  
Rna Polymerase ◽  
Transcriptional Control ◽  
Specific Binding ◽  
Rna Polymerase I ◽  
Rdna Transcription ◽  
Nucleolar Dominance ◽  
Cell Extracts ◽  
Species Specific ◽  
Polymerase I

RNA polymerase I transcription factors were purified from HeLa and mouse L cell extracts by phosphocellulose chromatography. Three fractions from each species were found to be required for transcription. One of these fractions, virtually devoid of RNA polymerase I activity, was found to form a stable preinitiation complex with small DNA fragments containing promoter sequences from the homologous but not the heterologous species. These species-specific DNA-binding factors can explain nucleolar dominance in vivo in mouse-human hybrid somatic cells and species specificity in cell-free, RNA polymerase I-dependent transcription systems. The evolution of species-specific transcriptional control signals may be the natural outcome of a special relationship that exists between the RNA polymerase I transcription machinery and the multigene family coding for rRNA.

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