Regulation of ribosome synthesis during compensatory renal hypertrophy in mice

1987 ◽  
Vol 253 (4) ◽  
pp. C506-C513 ◽  
Author(s):  
A. J. Ouellette ◽  
R. Moonka ◽  
A. D. Zelenetz ◽  
R. A. Malt
Keyword(s):  
Ribosomal Protein ◽  
Ribosomal Proteins ◽  
Rdna Transcription ◽  
Renal Hypertrophy ◽  
Renal Growth ◽  
Compensatory Renal Hypertrophy ◽  
Steady State Levels ◽  
Precursor Rna ◽  
Ribosomal Precursor

Ribosomal synthesis was studied at the transcriptional and translational levels to investigate the mechanisms of ribosome accretion during compensatory renal hypertrophy. As measured by in vitro transcriptional runoff comparisons 6-48 h after surgery, nuclei from the kidney remaining after contralateral nephrectomy show an increase of up to 150% in the rate of synthesis of ribosomal precursor RNA. The rate of rDNA transcription is 40-50% greater than control values as early as 6 h after nephrectomy; by 48 h, the rate returns to normal. In contrast to the stimulated transcription of rDNA and accretion of rRNA, the steady-state levels and the cytoplasmic distribution of ribosomal protein mRNAs S16 and L10 remain unchanged during induced renal growth. Thus coordinate production of adequate protein for increased assembly of ribosomes during induced renal growth appears to be accomplished by increasingly efficient translation of existing ribosomal protein mRNAs or by post-translational stabilization of ribosomal proteins. The rate of rDNA transcription may be regulated by accelerating the transcription of already functioning genes or, more likely, by recruiting transcription units that are transcriptionally inactive in the normal kidney.

scholarly journals Ribonucleic acid labelling and nucleotide pools during compensatory renal hypertrophy

1974 ◽  
Vol 144 (3) ◽  
pp. 447-453 ◽  
Author(s):  
J M Hill ◽  
G Ab ◽  
R A Malt
Keyword(s):  
Rna Synthesis ◽  
Single Injection ◽  
Specific Radioactivity ◽  
Compensatory Hypertrophy ◽  
Rrna Synthesis ◽  
Renal Hypertrophy ◽  
Rna Content ◽  
Compensatory Renal Hypertrophy ◽  
Precursor Rna ◽  
Ribosomal Precursor

During the first 48h of compensatory renal hypertrophy induced by unilateral nephrectomy, RNA content per cell increased by 20–40%. During this period, rates of RNA synthesis derived from the rates of labelling of UTP and RNA after a single injection of [5-3H]uridine showed no change in the rate of RNA synthesis (3.1nmol of UTP incorporated into RNA/min per mg of RNA). ATP and ADP pools were not changed. The rate of RNA synthesis was considerably in excess of the increment of total RNA appearing in the kidneys. With [5-3H]uridine as label, only continuous infusion for 24h could produce an increase (60%) in the specific radioactivity of renal rRNA in mice with contralateral nephrectomies. With a single injection of [methyl-3H]methionine used to identify methyl groups inserted into newly synthesized rRNA, the specific radioactivity of this rRNA was unchanged 5h after contralateral nephrectomy, increased by 60% at 9–48h, and returned to normal values at 120h. Most RNA synthesized in both nephrectomized and sham-nephrectomized mice has a short half-life. Since total cellular RNA content increases in compensatory hypertrophy despite unchanged rates of rRNA synthesis, the accretion of RNA might involve conservation of ribosomal precursor RNA or a change in rate of degradation of mature rRNA.

N6-methyladenosine residues in an intron-specific region of prolactin pre-mRNA

1990 ◽  
Vol 10 (9) ◽  
pp. 4456-4465
Author(s):  
S M Carroll ◽  
P Narayan ◽  
F M Rottman
Keyword(s):  
Consensus Sequence ◽  
Specific Sequence ◽  
Free System ◽  
Consensus Sequences ◽  
Neplanocin A ◽  
A Cell ◽  
Steady State Levels ◽  
Precursor Rna

N6-methyladenosine (m6A) residues occur at internal positions in most cellular and viral RNAs; both heterogeneous nuclear RNA and mRNA are involved. This modification arises by enzymatic transfer of a methyl group from S-adenosylmethionine to the central adenosine residue in the canonical sequence G/AAC. Thus far, m6A has been mapped to specific locations in eucaryotic mRNA and viral genomic RNA. We have now examined an intron-specific sequence of a modified bovine prolactin precursor RNA for the presence of this methylated nucleotide by using both transfected-cell systems and a cell-free system capable of methylating mRNA transcripts in vitro. The results indicate the final intron-specific sequence (intron D) of a prolactin RNA molecule does indeed possess m6A residues. When mapped to specific T1 oligonucleotides, the predominant site of methylation was found to be within the consensus sequence AGm6ACU. The level of m6A at this site is nonstoichiometric; approximately 24% of the molecules are modified in vivo. Methylation was detected at markedly reduced levels at other consensus sites within the intron but not in T1 oligonucleotides which do not contain either AAC or GAC consensus sequences. In an attempt to correlate mRNA methylation with processing, stably transfected CHO cells expressing augmented levels of bovine prolactin were treated with neplanocin A, an inhibitor of methylation. Under these conditions, the relative steady-state levels of the intron-containing nuclear precursor increased four to six times that found in control cells.

scholarly journals In Vitro Selection of Resistance in Haemophilus influenzae by Amoxicillin-Clavulanate, Cefpodoxime, Cefprozil, Azithromycin, and Clarithromycin

2002 ◽  
Vol 46 (9) ◽  
pp. 2956-2962 ◽  
Author(s):  
Catherine Clark ◽  
Bülent Bozdogan ◽  
Mihaela Peric ◽  
Bonifacio Dewasse ◽  
Michael R. Jacobs ◽  
...  
Keyword(s):  
Haemophilus Influenzae ◽  
Ribosomal Protein ◽  
Ribosomal Proteins ◽  
In Vitro Selection ◽  
Fold Increase ◽  
Single Step ◽  
23S Rrna ◽  
Gene Encoding ◽  
Amoxicillin Clavulanate

ABSTRACT Abilities of amoxicillin-clavulanate, cefpodoxime, cefprozil, azithromycin, and clarithromycin to select resistant mutants of Haemophilus influenzae were tested by multistep and single-step methodologies. For multistep studies, 10 random strains were tested: 5 of these were β-lactamase positive. After 50 daily subcultures in amoxicillin-clavulanate, MICs did not increase more than fourfold. However, cefprozil MICs increased eightfold for one strain. Clarithromycin and azithromycin gave a >4-fold increase in 8 and 10 strains after 14 to 46 and 20 to 50 days, respectively. Mutants selected by clarithromycin and azithromycin were associated with mutations in 23S rRNA and ribosomal proteins L4 and L22. Three mutants selected by clarithromycin or azithromycin had alterations in ribosomal protein L4, while five had alterations in ribosomal protein L22. Two mutants selected by azithromycin had mutations in the gene encoding 23S rRNA: one at position 2058 and the other at position 2059 (Escherichia coli numbering), with replacement of A by G. One clone selected by clarithromycin became hypersusceptible to macrolides. In single-step studies azithromycin and clarithromycin had the highest mutation rates, while amoxicillin-clavulanate had the lowest. All resistant clones were identical to parents as observed by pulsed-field gel electrophoresis. The MICs of azithromycin for azithromycin-resistant clones were 16 to >128 μg/ml, and those of clarithromycin for clarithromycin-resistant clones were 32 to >128 μg/ml in multistep studies. For strains selected by azithromycin, the MICs of clarithromycin were high and vice versa. After 50 daily subcultures in the presence of drugs, MICs of amoxicillin-clavulanate and cefpodoxime against H. influenzae did not rise more than fourfold, in contrast to cefprozil, azithromycin, and clarithromycin, whose MICs rose to variable degrees.

The relationship between the spoT gene, the synthesis of stable RNA, ribosomal proteins, and the ββ′ subunits of RNA polymerase following a nutritional shiftup of Escherichia coli

1978 ◽  
Vol 56 (6) ◽  
pp. 528-533 ◽  
Author(s):  
Stephen M. Boyle ◽  
Frederick Chu ◽  
Nathan Brot ◽  
Bruce H. Sells
Keyword(s):  
Escherichia Coli ◽  
Rna Polymerase ◽  
Ribosomal Protein ◽  
Ribosomal Proteins ◽  
Rna Synthesis ◽  
Transient Increase ◽  
Spot Gene ◽  
The Relationship

The level of ppGpp and rates of synthesis of stable RNA, ribosomal protein, and the β and β′ subunits of RNA polymerase were measured following a nutritional shiftup in Escherichia coli strains, NF 929 (spoT+) and NF 930 (spoT'−). In the spoT+ strain, ppGpp levels decreased 50% within 2 min following shiftup, and the rates of synthesis of stable RNA, ribosomal proteins, and the β and β′ subunits of RNA polymerase increased with little or no lag. In contrast, in the spoT− strain, ppGpp levels transiently increased 40% during the first 6 min following shiftup. An inhibition in the rate of stable RNA synthesis and a delay in the increased synthesis of ribosomal proteins and β and β′ subunits occurred concurrently with the transient increase in ppGpp. In addition, the DNA-dependent synthesis in vitro of the β and β′ subunits of RNA polymerase was inhibited by physiological levels of ppGpp. Because of the timing and magnitude of the changes in ppGpp levels in the spoT− strain versus the timing when the new rates of stable RNA, ribosomal protein, and β and β′ subunits synthesis are reached, it is concluded that ppGpp is not the sole element regulating the expression of these genes.

scholarly journals Phosphorylation of ribosomal protein S6 mediates compensatory renal hypertrophy

2015 ◽  
Vol 87 (3) ◽  
pp. 543-556 ◽  
Author(s):  
Jinxian Xu ◽  
Jianchun Chen ◽  
Zheng Dong ◽  
Oded Meyuhas ◽  
Jian-Kang Chen
Keyword(s):  
Ribosomal Protein ◽  
Renal Hypertrophy ◽  
Ribosomal Protein S6 ◽  
Compensatory Renal Hypertrophy

Structure and expression of ribosomal protein genes in Xenopus laevis

1995 ◽  
Vol 73 (11-12) ◽  
pp. 969-977 ◽  
Author(s):  
Francesco Amaldi ◽  
Olga Camacho-Vanegas ◽  
Francesco Cecconi ◽  
Fabrizio Loreni ◽  
Beatrice Cardinali ◽  
...  
Keyword(s):  
Xenopus Laevis ◽  
Ribosomal Protein ◽  
Ribosomal Proteins ◽  
Translational Regulation ◽  
Cultured Cells ◽  
Structural Features ◽  
Ribosomal Protein Genes ◽  
Translation Apparatus ◽  
And Function

In Xenopus laevis, as well as in other vertebrates, ribosomal proteins (r-proteins) are coded by a class of genes that share some organizational and structural features. One of these, also common to genes coding for other proteins involved in the translation apparatus synthesis and function, is the presence within their introns of sequences coding for small nucleolar RNAs. Another feature is the presence of common structures, mainly in the regions surrounding the 5′ ends, involved in their coregulated expression. This is attained at various regulatory levels: transcriptional, posttranscriptional, and translational. Particular attention is given here to regulation at the translational level, which has been studied during Xenopus oogenesis and embryogenesis and also during nutritional changes of Xenopus cultured cells. This regulation, which responds to the cellular need for new ribosomes, operates by changing the fraction of rp-mRNA (ribosomal protein mRNA) engaged on polysomes. A typical 5′ untranslated region characterizing all vertebrate rp-mRNAs analyzed to date is responsible for this translational behaviour: it is always short and starts with an 8–12 nucleotide polypyrimidine tract. This region binds in vitro some proteins that can represent putative trans-acting factors for this translational regulation.Key words: ribosomal proteins, snoRNA, translational regulation, Xenopus laevis.

scholarly journals N6-methyladenosine residues in an intron-specific region of prolactin pre-mRNA.

1990 ◽  
Vol 10 (9) ◽  
pp. 4456-4465 ◽  
Author(s):  
S M Carroll ◽  
P Narayan ◽  
F M Rottman
Keyword(s):  
Consensus Sequence ◽  
Specific Sequence ◽  
Free System ◽  
Consensus Sequences ◽  
Neplanocin A ◽  
A Cell ◽  
Steady State Levels ◽  
Precursor Rna

N6-methyladenosine (m6A) residues occur at internal positions in most cellular and viral RNAs; both heterogeneous nuclear RNA and mRNA are involved. This modification arises by enzymatic transfer of a methyl group from S-adenosylmethionine to the central adenosine residue in the canonical sequence G/AAC. Thus far, m6A has been mapped to specific locations in eucaryotic mRNA and viral genomic RNA. We have now examined an intron-specific sequence of a modified bovine prolactin precursor RNA for the presence of this methylated nucleotide by using both transfected-cell systems and a cell-free system capable of methylating mRNA transcripts in vitro. The results indicate the final intron-specific sequence (intron D) of a prolactin RNA molecule does indeed possess m6A residues. When mapped to specific T1 oligonucleotides, the predominant site of methylation was found to be within the consensus sequence AGm6ACU. The level of m6A at this site is nonstoichiometric; approximately 24% of the molecules are modified in vivo. Methylation was detected at markedly reduced levels at other consensus sites within the intron but not in T1 oligonucleotides which do not contain either AAC or GAC consensus sequences. In an attempt to correlate mRNA methylation with processing, stably transfected CHO cells expressing augmented levels of bovine prolactin were treated with neplanocin A, an inhibitor of methylation. Under these conditions, the relative steady-state levels of the intron-containing nuclear precursor increased four to six times that found in control cells.

scholarly journals Prefabrication of a ribosomal protein subcomplex essential for eukaryotic ribosome formation

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Cohue Peña ◽  
Sabina Schütz ◽  
Ute Fischer ◽  
Yiming Chang ◽  
Vikram G Panse
Keyword(s):  
Atpase Activity ◽  
Structural Feature ◽  
Ribosomal Protein ◽  
Ribosomal Proteins ◽  
Spatial Clustering ◽  
Functional Importance ◽  
Eukaryotic Ribosome ◽  
Ribosome Formation

Spatial clustering of ribosomal proteins (r-proteins) through tertiary interactions is a striking structural feature of the eukaryotic ribosome. However, the functional importance of these intricate inter-connections, and how they are established is currently unclear. Here, we reveal that a conserved ATPase, Fap7, organizes interactions between neighboring r-proteins uS11 and eS26 prior to their delivery to the earliest ribosome precursor, the 90S. In vitro, uS11 only when bound to Fap7 becomes competent to recruit eS26 through tertiary contacts found between these r-proteins on the mature ribosome. Subsequently, Fap7 ATPase activity unloads the uS11:eS26 subcomplex onto its rRNA binding site, and therefore ensures stoichiometric integration of these r-proteins into the 90S. Fap7-depletion in vivo renders uS11 susceptible to proteolysis, and precludes eS26 incorporation into the 90S. Thus, prefabrication of a native-like r-protein subcomplex drives efficient and accurate construction of the eukaryotic ribosome.

scholarly journals A memory of eS25 loss drives resistance phenotypes

2020 ◽  
Author(s):  
Alex G Johnson ◽  
Ryan A Flynn ◽  
Christopher P Lapointe ◽  
Yaw Shin Ooi ◽  
Michael L Zhao ◽  
...  
Keyword(s):  
Ribosomal Protein ◽  
Translational Control ◽  
Ribosomal Proteins ◽  
Ribosomal Protein Gene ◽  
Human Cell Line ◽  
Cellular Protein ◽  
Ribosomal Protein Genes ◽  
Genomic Locus ◽  
Cellular Phenotypes

Abstract In order to maintain cellular protein homeostasis, ribosomes are safeguarded against dysregulation by myriad processes. Remarkably, many cell types can withstand genetic lesions of certain ribosomal protein genes, some of which are linked to diverse cellular phenotypes and human disease. Yet the direct and indirect consequences from these lesions are poorly understood. To address this knowledge gap, we studied in vitro and cellular consequences that follow genetic knockout of the ribosomal proteins RPS25 or RACK1 in a human cell line, as both proteins are implicated in direct translational control. Prompted by the unexpected detection of an off-target ribosome alteration in the RPS25 knockout, we closely interrogated cellular phenotypes. We found that multiple RPS25 knockout clones display viral- and toxin-resistance phenotypes that cannot be rescued by functional cDNA expression, suggesting that RPS25 loss elicits a cell state transition. We characterized this state and found that it underlies pleiotropic phenotypes and has a common rewiring of gene expression. Rescuing RPS25 expression by genomic locus repair failed to correct for the phenotypic and expression hysteresis. Our findings illustrate how the elasticity of cells to a ribosome perturbation can drive specific phenotypic outcomes that are indirectly linked to translation and suggests caution in the interpretation of ribosomal protein gene mutation data.

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