scholarly journals Arabidopsis REI-LIKE proteins activate ribosome biogenesis during cold acclimation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bo Eng Cheong ◽  
Olga Beine-Golovchuk ◽  
Michal Gorka ◽  
William Wing Ho Ho ◽  
Federico Martinez-Seidel ◽  
...  
Keyword(s):  
Steady State ◽  
Feedback Control ◽  
Cold Acclimation ◽  
Ribosomal Proteins ◽  
Ribosome Biogenesis ◽  
Transcriptional Control ◽  
De Novo ◽  
De Novo Synthesis ◽  
Steady State Temperature

AbstractArabidopsis REIL proteins are cytosolic ribosomal 60S-biogenesis factors. After shift to 10 °C, reil mutants deplete and slowly replenish non-translating eukaryotic ribosome complexes of root tissue, while controlling the balance of non-translating 40S- and 60S-subunits. Reil mutations respond by hyper-accumulation of non-translating subunits at steady-state temperature; after cold-shift, a KCl-sensitive 80S sub-fraction remains depleted. We infer that Arabidopsis may buffer fluctuating translation by pre-existing non-translating ribosomes before de novo synthesis meets temperature-induced demands. Reil1 reil2 double mutants accumulate 43S-preinitiation and pre-60S-maturation complexes and alter paralog composition of ribosomal proteins in non-translating complexes. With few exceptions, e.g. RPL3B and RPL24C, these changes are not under transcriptional control. Our study suggests requirement of de novo synthesis of eukaryotic ribosomes for long-term cold acclimation, feedback control of NUC2 and eIF3C2 transcription and links new proteins, AT1G03250, AT5G60530, to plant ribosome biogenesis. We propose that Arabidopsis requires biosynthesis of specialized ribosomes for cold acclimation.

scholarly journals Arabidopsis REI-LIKE proteins activate ribosome biogenesis during cold acclimation

2020 ◽  
Author(s):  
Bo Eng Cheong ◽  
Olga Beine-Golovchuk ◽  
Michal Gorka ◽  
William Wing Ho Ho ◽  
Federico Martinez-Seidel ◽  
...  
Keyword(s):  
Steady State ◽  
Feedback Control ◽  
Cold Acclimation ◽  
Ribosomal Proteins ◽  
Ribosome Biogenesis ◽  
Transcriptional Control ◽  
De Novo ◽  
Eukaryotic Ribosome ◽  
Steady State Temperature

AbstractArabidopsis REIL proteins are cytosolic ribosomal 60S-biogenesis factors. After shift to 10°C, reil mutants deplete and slowly replenish non-translating eukaryotic ribosome complexes of root tissue, while tightly controlling the balance of non-translating 40S- and 60S-subunits. Reil mutations compensate by hyper-accumulation of non-translating subunits at steady-state temperature; after cold-shift, a KCl-sensitive 80S sub-fraction remains depleted. We infer that Arabidopsis buffers fluctuating translation by pre-existing non-translating ribosomes before de novo synthesis meets temperature-induced demands. Reil1 reil2 double mutants accumulate 43S-preinitiation and pre-60S-maturation complexes and have altered paralog composition of ribosomal proteins in non-translating complexes. With few exceptions, e.g. RPL3B and RPL24C, these changes are not under transcriptional control. Our study suggests requirement of de novo synthesis of eukaryotic ribosomes for long-term cold acclimation, feedback control of NUC2 and eIF3C2 transcription and links new proteins, AT1G03250, AT5G60530, to plant ribosome biogenesis. We propose that Arabidopsis requires biosynthesis of specialized ribosomes for cold acclimation.Highlight of this studyREIL proteins affect paralog composition of eukaryotic ribosomes and suppress accumulation of 43S-preinitiation and pre-60S-maturation complexes, suggesting functions of ribosome heterogeneity and biogenesis in plant cold acclimation.

Divergent effects of intravenous GSH and cysteine on renal and hepatic GSH

1992 ◽  
Vol 263 (2) ◽  
pp. R348-R352 ◽  
Author(s):  
S. Aebi ◽  
B. H. Lauterburg
Keyword(s):  
Steady State ◽  
De Novo ◽  
Feedback Inhibition ◽  
Therapeutic Use ◽  
Steady State Concentration ◽  
De Novo Synthesis ◽  
State Concentration ◽  
Cellular Thiol

There is a growing interest in the therapeutic use of sulfhydryls. To assess the effect of glutathione (GSH) and cysteine on the cellular thiol status, thiols were administered intravenously to rats in doses ranging from 1.67 to 8.35 mmol/kg with and without pretreatment with 4 mmol/kg buthionine-[S,R]-sulfoximine (BSO), an inhibitor of GSH synthesis. One hour after administration of 1.67 mmol/kg GSH, the concentration of GSH rose from 5.2 +/- 1.0 to 8.4 +/- 0.9 mumol/g and from 2.5 +/- 0.5 to 3.7 +/- 0.7 mumol/g in liver and kidneys, respectively. After 8.35 mmol/kg, hepatic GSH did not increase further, but renal GSH rose to 6.7 +/- 1.8 mumol/g. Infusion of cysteine increased hepatic GSH to the same extent as intravenous GSH, but renal GSH did not increase after 1.67 mmol/kg and even significantly decreased to 0.6 +/- 0.2 mumol/g after 8.35 mmol/kg. In the presence of BSO, GSH resulted in a significant increase in renal but not hepatic GSH, suggesting that the kidneys take up intact GSH and indicating that the increment in hepatic GSH was due to de novo synthesis. The present data show that hepatic GSH can be markedly increased in vivo by increasing the supply of cysteine. Measurements of hepatic cysteine indicate that up to a concentration of approximately 0.5 mumol/g cysteine is a key determinant of hepatic GSH, such that the physiological steady-state concentration of GSH in the liver appears to be mainly determined by the availability of cysteine. At higher concentrations GSH does not increase further, possibly due to feedback inhibition of GSH synthesis or increased efflux.(ABSTRACT TRUNCATED AT 250 WORDS)

De novo Synthesis and Assembly of rRNA into Ribosomal Subunits during Cold Acclimation in Escherichia coli

2016 ◽  
Vol 428 (8) ◽  
pp. 1558-1573 ◽  
Author(s):  
Lolita Piersimoni ◽  
Mara Giangrossi ◽  
Paolo Marchi ◽  
Anna Brandi ◽  
Claudio O. Gualerzi ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cold Acclimation ◽  
De Novo ◽  
De Novo Synthesis ◽  
Ribosomal Subunits

scholarly journals Changes in the expression of alpha-fodrin during embryonic development of Xenopus laevis.

1987 ◽  
Vol 105 (2) ◽  
pp. 843-853 ◽  
Author(s):  
D H Giebelhaus ◽  
B D Zelus ◽  
S K Henchman ◽  
R T Moon
Keyword(s):  
Steady State ◽  
Embryonic Development ◽  
Xenopus Laevis ◽  
De Novo ◽  
Single Gene ◽  
Predicted Amino Acid Sequence ◽  
Cdna Clones ◽  
De Novo Synthesis ◽  
S1 Nuclease ◽  
Stage Of Development

Fodrin (nonerythroid spectrin) and its associated proteins have been previously implicated in the establishment of specialized membrane-cytoskeletal domains in differentiating cells. Using antiserum which is monospecific for the alpha-subunit of fodrin, we demonstrate that alpha-fodrin is present in oocytes and adult tissues of Xenopus laevis. Analyses of the de novo synthesis of alpha-fodrin during embryonic development reveal that alpha-fodrin is synthesized in oocytes, but not during early development. To investigate the level of control of alpha-fodrin expression, we isolated two cDNA clones for oocyte alpha-fodrin. The oocyte cDNA clones were identified as encoding portions of alpha-fodrin based on DNA sequence analysis and on the comparison of the predicted amino acid sequence of the cDNAs with the known sequence of human erythrocyte alpha-spectrin. The Xenopus alpha-fodrin cDNAs hybridize to a transcript of approximately 9 kb on RNA blots, and probably to a single gene type on genomic DNA blots. Both RNA blot analyses and S1 nuclease protection assays with the Xenopus alpha-fodrin cDNAs demonstrate that the observed decline in the de novo synthesis of alpha-fodrin polypeptides is controlled by a dramatic decrease in the abundance of alpha-fodrin transcripts after fertilization. In contrast, levels of actin transcripts do not decrease during this period. Inasmuch as steady-state levels of alpha-fodrin transcripts rise by the neurula stage of development, these results suggest that the synthesis of alpha-fodrin polypeptides during embryonic development of Xenopus is regulated, rather than constitutive, and that the primary level of control is the steady-state abundance of mRNA.

scholarly journals A functional connection between translation elongation and protein folding at the ribosome exit tunnel in Saccharomyces cerevisiae

2020 ◽  
Author(s):  
Olga Rodríguez-Galán ◽  
Juan J García-Gómez ◽  
Iván V Rosado ◽  
Wu Wei ◽  
Alfonso Méndez-Godoy ◽  
...  
Keyword(s):  
Ribosomal Proteins ◽  
Ribosome Biogenesis ◽  
De Novo ◽  
Peptide Bond Formation ◽  
Peptidyl Transferase ◽  
Translation Rate ◽  
Functional Connection ◽  
Translation Elongation ◽  
Peptidyl Transferase Center ◽  
Exit Tunnel

Abstract Proteostasis needs to be tightly controlled to meet the cellular demand for correctly de novo folded proteins and to avoid protein aggregation. While a coupling between translation rate and co-translational folding, likely involving an interplay between the ribosome and its associated chaperones, clearly appears to exist, the underlying mechanisms and the contribution of ribosomal proteins remain to be explored. The ribosomal protein uL3 contains a long internal loop whose tip region is in close proximity to the ribosomal peptidyl transferase center. Intriguingly, the rpl3[W255C] allele, in which the residue making the closest contact to this catalytic site is mutated, affects diverse aspects of ribosome biogenesis and function. Here, we have uncovered, by performing a synthetic lethal screen with this allele, an unexpected link between translation and the folding of nascent proteins by the ribosome-associated Ssb-RAC chaperone system. Our results reveal that uL3 and Ssb-RAC cooperate to prevent 80S ribosomes from piling up within the 5′ region of mRNAs early on during translation elongation. Together, our study provides compelling in vivo evidence for a functional connection between peptide bond formation at the peptidyl transferase center and chaperone-assisted de novo folding of nascent polypeptides at the solvent-side of the peptide exit tunnel.

scholarly journals Transcriptional control of ribosome biogenesis in yeast: links to growth and stress signals

2021 ◽  
Author(s):  
David Shore ◽  
Sevil Zencir ◽  
Benjamin Albert
Keyword(s):  
Ribosomal Proteins ◽  
Ribosome Biogenesis ◽  
Transcriptional Control ◽  
Yeast Cells ◽  
Ribosomal Protein Genes ◽  
Recent Developments ◽  
Pioneer Transcription Factor ◽  
Stress Signals ◽  
Transcriptional Output ◽  
Major Recent Development

Ribosome biogenesis requires prodigious transcriptional output in rapidly growing yeast cells and is highly regulated in response to both growth and stress signals. This minireview focuses on recent developments in our understanding of this regulatory process, with an emphasis on the 138 ribosomal protein genes (RPGs) themselves and a group of >200 ribosome biogenesis (RiBi) genes whose products contribute to assembly but are not part of the ribosome. Expression of most RPGs depends upon Rap1, a pioneer transcription factor (TF) required for the binding of a pair of RPG-specific TFs called Fhl1 and Ifh1. RPG expression is correlated with Ifh1 promoter binding, whereas Rap1 and Fhl1 remain promoter-associated upon stress-induced down regulation. A TF called Sfp1 has also been implicated in RPG regulation, though recent work reveals that its primary function is in activation of RiBi and other growth-related genes. Sfp1 plays an important regulatory role at a small number of RPGs where Rap1–Fhl1–Ifh1 action is subsidiary or non-existent. In addition, nearly half of all RPGs are bound by Hmo1, which either stabilizes or re-configures Fhl1–Ifh1 binding. Recent studies identified the proline rotamase Fpr1, known primarily for its role in rapamycin-mediated inhibition of the TORC1 kinase, as an additional TF at RPG promoters. Fpr1 also affects Fhl1–Ifh1 binding, either independently or in cooperation with Hmo1. Finally, a major recent development was the discovery of a protein homeostasis mechanism driven by unassembled ribosomal proteins, referred to as the Ribosome Assembly Stress Response (RASTR), that controls RPG transcription through the reversible condensation of Ifh1.

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