Regulation of ribosomal RNA synthesis in Tetrahymena pyriformis

1978 ◽  
Vol 31 (1) ◽  
pp. 13-23
Author(s):  
J. Keiding ◽  
H.A. Andersen
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Ribosomal Rna ◽  
Rna Synthesis ◽  
Tetrahymena Pyriformis ◽  
Rrna Synthesis ◽  
Constant Rate ◽  
Normal Increase ◽  
S Period ◽  
Dosis Effect

Ribosomal RNA is synthesized at constant rate during most of the cell cycle in heat-shock synchronized populations of Tetrahymena pyriformis. Early in each macronuclear S-period the rate of synthesis increases abruptly, concomitant with replication of the genes coding for ribosomal RNA. The increase is prevented by inhibitors of DNA replication, added prior to the S-period. Similarly, in cultures synchronized by starvation/refeeding, inhibition of DNA replication, at the time when the rDNA is replicated, will prevent the normal increase in rate of RNA synthesis which follows refeeding. We conclude that inhibition of rDNA replication interferes with the synthesis of rRNA, and we suggest that with respect to rRNA synthesis a gene dosis effect is operating in fast-growing Tetrahymena cells.

Inhibition of rRNA synthesis following incorporation of 5-bromodeoxyuridine into DNA of Tetrahymena pyriformis

1975 ◽  
Vol 17 (3) ◽  
pp. 495-502
Author(s):  
A.E. Lykkesfeldt ◽  
H.A. Andersen
Keyword(s):  
Dna Replication ◽  
Ribosomal Rna ◽  
Rna Synthesis ◽  
Nuclear Dna ◽  
Tetrahymena Pyriformis ◽  
Growth Conditions ◽  
Defined Medium ◽  
Rrna Synthesis ◽  
Chemically Defined Medium ◽  
Dividing Cells

Tetrahymena pyriformis was grown on chemically defined medium in the presence of 5-bromodeoxyuridine (BUdR). Under these growth conditions more than 60% of the thymidine sites in DNA were substituted with BUdR. It was found that RNA synthesis was strongly inhibited by the presence of BUdR in DNA. To assure that incorporation of BUdR into DNA was a prerequisite of the effect observed, BUdR was added to synchronously dividing cells. BUdR had no effect on the cells when present outside the period of nuclear DNA replication, whereas RNA synthesis was strongly inhibited as soon as the genes coding for ribosomal RNA had replicated in the presence of BUdR.

Preferential inhibition of rDNA transcription by 5-bromodeoxyuridine

1977 ◽  
Vol 25 (1) ◽  
pp. 95-102
Author(s):  
A.E. Lykkesfeldt ◽  
H.A. Andersen
Keyword(s):  
Growth Medium ◽  
Ribosomal Rna ◽  
Rna Synthesis ◽  
Tetrahymena Pyriformis ◽  
Degree Of Substitution ◽  
Rdna Transcription ◽  
Total Rna

On a chemically defined growth medium the degree of substitution of thymidine with 5-bromodeoxyuridine (BUdR) in DNA of Tetrahymena pyriformis was controlled by the concentration of tetrahydrofiolic acid, BUdR and thymidine in the medium. A correlation between the degree of BUdR substitution in DNA and the reduction in rate of total RNA synthesis has been established. It was found that the reduction of total RNA synthesis results from inhibition of transcription of all RNA species which have been measured. However, independent of the degree of BUdR substitution in DNA, a preferential inhibition of the synthesis of 25s and 17s ribosomal RNA was found. It is concluded that the various genes may respond differently to BUdR substitution with respect to transcription.

Wachstumsparameter in normalen und durch Actinomycin verlängerten Zellzyklen von Tetrahymena / Growth Parameters in Normal and Actinomycin-induced prolonged Cell Cycles of Tetrahymena

1969 ◽  
Vol 24 (12) ◽  
pp. 1624-1629 ◽  
Author(s):  
Günter Cleffmann
Keyword(s):  
Cell Cycle ◽  
Protein Synthesis ◽  
Cell Division ◽  
Dna Replication ◽  
Cell Growth ◽  
Rna Synthesis ◽  
Growth Parameters ◽  
Average Duration ◽  
Cell Cycles ◽  
Growing Cell

Actinomycin in low concentration (0,2 μg/ml — 0,5 μg/ml) prolongs the average duration of the cell cycle of Tetrahymena considerably, but does not inhibit cell division completely. Some parameters of the growing cell have been tested in cell cycles extended in this way and compared to those of normally growing cells. The RNA synthesis of treated cells is reduced to such an extent that the RNA content per cell decreases during the prolonged cell cycle. Nevertheless cell growth, protein synthesis and DNA replication proceed at almost the same rate as in untreated cells. These findings indicate that the presence of actinomycin does not interfere with RNA fractions necessary for growth but reduce the synthesis of RNA fractions which are essential for cell division. Therefore a longer period is needed for their accumulation.

scholarly journals REGULATION OF RIBOSOMAL RNA AND 5s RNA SYNTHESIS IN DROSOPHILA MELANOGASTER: I. BOBBED MUTANTS

Genetics ◽  
1972 ◽  
Vol 72 (2) ◽  
pp. 267-276
Author(s):  
Roberto Weinmann
Keyword(s):  
Drosophila Melanogaster ◽  
Developmental Delay ◽  
Ribosomal Rna ◽  
Gel Electrophoresis ◽  
Rna Synthesis ◽  
Rrna Synthesis ◽  
Wild Type ◽  
5S Rna ◽  
Wild Type Level

ABSTRACT Analysis of the rates and amounts of rRNA and 5s RNA synthesized in Drosophila melanogaster bobbed mutants was done by using acrylamide-gel electrophoresis. The results show that the amounts of rRNA synthesized are constant, although the rates of rRNA synthesis in bb's are reduced to 30% of the wild-type level. The rates of synthesis of 5s RNA were constant. The rate of synthesis of the two kinds of molecules that enter in equimolar amounts into the mature ribosome is non-coordinated.—The rates of rRNA synthesis were shown to be proportional to the length of the scutellar bristles, supporting the notion that in trichogen cells there is no developmental delay, but the size of the bristle depends directly on the rate of rRNA synthesis.

scholarly journals Che-1/AATF binds to RNA polymerase I machinery and sustains ribosomal RNA gene transcription

2020 ◽  
Vol 48 (11) ◽  
pp. 5891-5906 ◽  
Author(s):  
Cristina Sorino ◽  
Valeria Catena ◽  
Tiziana Bruno ◽  
Francesca De Nicola ◽  
Stefano Scalera ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Rna Polymerase ◽  
Ribosomal Rna ◽  
Ribosome Biogenesis ◽  
Cellular Proliferation ◽  
Rna Polymerase I ◽  
Rrna Synthesis ◽  
Rrna Gene ◽  
Response To Stress ◽  
Polymerase I

Abstract Originally identified as an RNA polymerase II interactor, Che-1/AATF (Che-1) has now been recognized as a multifunctional protein involved in cell-cycle regulation and cancer progression, as well as apoptosis inhibition and response to stress. This protein displays a peculiar nucleolar localization and it has recently been implicated in pre-rRNA processing and ribosome biogenesis. Here, we report the identification of a novel function of Che-1 in the regulation of ribosomal RNA (rRNA) synthesis, in both cancer and normal cells. We demonstrate that Che-1 interacts with RNA polymerase I and nucleolar upstream binding factor (UBF) and promotes RNA polymerase I-dependent transcription. Furthermore, this protein binds to the rRNA gene (rDNA) promoter and modulates its epigenetic state by contrasting the recruitment of HDAC1. Che-1 downregulation affects RNA polymerase I and UBF recruitment on rDNA and leads to reducing rDNA promoter activity and 47S pre-rRNA production. Interestingly, Che-1 depletion induces abnormal nucleolar morphology associated with re-distribution of nucleolar proteins. Finally, we show that upon DNA damage Che-1 re-localizes from rDNA to TP53 gene promoter to induce cell-cycle arrest. This previously uncharacterized function of Che-1 confirms the important role of this protein in the regulation of ribosome biogenesis, cellular proliferation and response to stress.

Rates of synthesis of polyadenylated messenger RNA and ribosomal RNA during the cell cycle of Schizosaccharomyces pombe. With an appendix: calculation of the pattern of protein accumulation from observed changes in the rate of messenger RNA synthesis

1976 ◽  
Vol 21 (3) ◽  
pp. 497-521
Author(s):  
R.S. Fraser ◽  
F. Moreno
Keyword(s):  
Cell Cycle ◽  
Dna Synthesis ◽  
Schizosaccharomyces Pombe ◽  
Ribosomal Rna ◽  
Messenger Rna ◽  
Rna Synthesis ◽  
Protein Accumulation ◽  
Synchronous Culture ◽  
Synchronous Cultures ◽  
Gene Copies

The rates of polyadenylated messenger RNA and ribosomal RNA synthesis were measured in synchronously dividing cultures of fission yeast (Schizosaccharomyces pombe). Control asynchronous cultures, which had been exposed to the conditions used for preparing synchronous cultures, were investigated to check for effects of the synchronization procedure itself on RNA synthesis. After each period of DNA synthesis in synchronous culture, the rates of messenger and ribosomal RNA synthesis doubled, suggesting that gene number controls the rate of messenger and ribosomal RNA synthesis. This was confirmed by experiments with asynchronous, exponential-phase cultures in which DNA synthesis was inhibited by hydroxyurea. Both synchronous culture and hydroxyurea experiments suggested that there is a delay of 15 min (0-1 of the cell generation time) between replication of the DNA and transcription of both gene copies. A pattern of protein accumulation was calculated from changes in the rate of polyadenylated messenger RNA synthesis during synchronous culture. The simulated pattern indicates that protein is accumulated linearly, with a doubling in the rate of accumulation once per cell cycle. The simulated pattern of protein accumulation is very similar to measurements previously reported by other workers of changes in activities of 3 enzymes in synchronous cultures. It is suggested that the doubling of the rate of messenger RNA synthesis, as a consequence of the replication of the DNA once per cycle, provides the basis of a mechanism for control of the doubling of other cellular constituents during the cell cycle.

scholarly journals WDR55 Is a Nucleolar Modulator of Ribosomal RNA Synthesis, Cell Cycle Progression, and Teleost Organ Development

PLoS Genetics ◽  
2008 ◽  
Vol 4 (8) ◽  
pp. e1000171 ◽  
Author(s):  
Norimasa Iwanami ◽  
Tomokazu Higuchi ◽  
Yumi Sasano ◽  
Toshinobu Fujiwara ◽  
Vu Q. Hoa ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Ribosomal Rna ◽  
Cell Cycle Progression ◽  
Rna Synthesis ◽  
Organ Development ◽  
Cycle Progression

scholarly journals Dependence of nucleus-directed rRNA synthesis upon mitochondrial protein synthesis in Tetrahymena.

1982 ◽  
Vol 2 (5) ◽  
pp. 508-516 ◽  
Author(s):  
L Ruben ◽  
A B Hooper
Keyword(s):  
Protein Synthesis ◽  
Rna Synthesis ◽  
Mitochondrial Protein ◽  
Tetrahymena Pyriformis ◽  
Cellular Protein ◽  
Rrna Synthesis ◽  
Mitochondrial Protein Synthesis ◽  
Mitochondrial Rrna ◽  
Polyadenylated Rna ◽  
Nuclear Rna

The antibiotic chloramphenicol selectively inhibited mitochondrial protein synthesis in the ciliate protozoan Tetrahymena pyriformis GL. Secondary to the inhibition of mitochondrial protein synthesis was an inhibition of nuclear RNA synthesis at a time before inhibition of cellular protein and DNA synthesis. Of the stable non-polyadenylated RNA species in Tetrahymena, the addition of chloramphenicol resulted specifically in the inhibition of synthesis of 28S + 17S and 5S rRNA transcripts. By contrast, syntheses of 4S tRNA and 21S mitochondrial rRNA were not as extensively inhibited. The addition of 60 microM hemin before the addition of chloramphenicol partially protected against the inhibition of RNA synthesis. These data indicate that continued synthesis of nucleus-directed rRNA is linked to the synthesis of mitochondrial proteins in Tetrahymena.

scholarly journals ANALYSIS OF THE SCHEDULE OF DNA REPLICATION IN HEAT-SYNCHRONIZED TETRAHYMENA

1973 ◽  
Vol 59 (1) ◽  
pp. 1-11 ◽  
Author(s):  
William R. Jeffery ◽  
Joseph Frankel ◽  
Lawrence E. de Bault ◽  
Leslie M. Jenkins
Keyword(s):  
Cell Cycle ◽  
High Temperature ◽  
Dna Replication ◽  
Heat Shock ◽  
Dna Synthesis ◽  
Shock Treatment ◽  
Heat Shock Treatment ◽  
Dividing Cells ◽  
S Period ◽  
Selection Of

The temporal schedule of DNA replication in heat-synchronized Tetrahymena was studied by autoradiographic and cytofluorometric methods. It was shown that some cells, which were synchronized by selection of individual dividing cells or by temporary thymidine starvation, incorporated [3H]thymidine into macronuclei in a periodic fashion during the heat-shock treatment. It was concluded that supernumerary S periods occurred while cell division was blocked by high temperature. The proportion of cells which initiated supernumerary S periods was found to be dependent on the duration of the heat-shock treatment and on the cell cycle stage when the first heat shock was applied. Cytofluorometric measurements of Feulgen-stained macronuclei during the heat-shock treatment indicated that the DNA complement of these cells was substantially increased and probably duplicated during the course of each S period. Estimates of DNA content also suggested that the rate of DNA synthesis progressively declined during long heat-shock treatments. These results indicate that the mechanism which brings about heat-induced division synchrony is not an interruption of the process of DNA replication. Further experiments were concerned with the regulation of DNA synthesis during the first synchronized division cycle. It was shown that participation in DNA synthesis at this time increased as more cells were able to conclude the terminal S period during the preceding heat-shock treatment. It is suggested that a discrete period of time is necessary after the completion of DNA synthesis before another round of DNA synthesis can be initiated.

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