scholarly journals snoRNPs: Functions in Ribosome Biogenesis

Biomolecules ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 783 ◽  
Author(s):  
Sandeep Ojha ◽  
Sulochan Malla ◽  
Shawn M. Lyons
Keyword(s):  
Protein Synthesis ◽  
Chemical Modification ◽  
Molecular Chaperones ◽  
Small Rnas ◽  
Ribosome Biogenesis ◽  
Multiple Roles ◽  
Complex Structures ◽  
Rrna Processing ◽  
Chemically Modified ◽  
Protein Components

Ribosomes are perhaps the most critical macromolecular machine as they are tasked with carrying out protein synthesis in cells. They are incredibly complex structures composed of protein components and heavily chemically modified RNAs. The task of assembling mature ribosomes from their component parts consumes a massive amount of energy and requires greater than 200 assembly factors. Among the most critical of these are small nucleolar ribonucleoproteins (snoRNPs). These are small RNAs complexed with diverse sets of proteins. As suggested by their name, they localize to the nucleolus, the site of ribosome biogenesis. There, they facilitate multiple roles in ribosomes biogenesis, such as pseudouridylation and 2′-O-methylation of ribosomal (r)RNA, guiding pre-rRNA processing, and acting as molecular chaperones. Here, we reviewed their activity in promoting the assembly of ribosomes in eukaryotes with regards to chemical modification and pre-rRNA processing.

scholarly journals TOP mRNPs: Molecular Mechanisms and Principles of Regulation

Biomolecules ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 969 ◽  
Author(s):  
Eric Cockman ◽  
Paul Anderson ◽  
Pavel Ivanov
Keyword(s):  
Protein Synthesis ◽  
Translational Control ◽  
Gene Networks ◽  
Cellular Response ◽  
Ribosome Biogenesis ◽  
Molecular Mechanisms ◽  
Mrna Translation ◽  
Ribonucleoprotein Complexes ◽  
Global Protein Synthesis ◽  
Protein Components

The cellular response to changes in the surrounding environment and to stress requires the coregulation of gene networks aiming to conserve energy and resources. This is often achieved by downregulating protein synthesis. The 5’ Terminal OligoPyrimidine (5’ TOP) motif-containing mRNAs, which encode proteins that are essential for protein synthesis, are the primary targets of translational control under stress. The TOP motif is a cis-regulatory RNA element that begins directly after the m7G cap structure and contains the hallmark invariant 5’-cytidine followed by an uninterrupted tract of 4–15 pyrimidines. Regulation of translation via the TOP motif coordinates global protein synthesis with simultaneous co-expression of the protein components required for ribosome biogenesis. In this review, we discuss architecture of TOP mRNA-containing ribonucleoprotein complexes, the principles of their assembly, and the modes of regulation of TOP mRNA translation.

scholarly journals Intronic non-coding RNAs within ribosomal protein coding genes can regulate biogenesis of yeast ribosome

2018 ◽  
Author(s):  
Akshara Pande ◽  
Rani Sharma ◽  
Bharat Ravi Iyengar ◽  
Vinod Scaria ◽  
Beena Pillai ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ribosomal Protein ◽  
Small Rnas ◽  
Ribosomal Proteins ◽  
Ribosome Biogenesis ◽  
Rdna Locus ◽  
Protein Coding ◽  
Protein Coding Genes ◽  
Protein Components ◽  
Retained Introns

AbstractThe genome of the budding yeast (Saccharomyces cerevisiae) has selectively retained introns in ribosomal protein coding genes. The function of these introns has remained elusive in spite of experimental evidence that they are required for the fitness of yeast. Here, we computationally predict novel small RNAs that arise from the intronic regions of ribosomal protein (RP) coding genes in Saccharomyces cerevisiae. Further, we experimentally validated the presence of seven intronic small RNAs (isRNAs). Computational predictions suggest that these isRNAs potentially bind to the ribosomal DNA (rDNA) locus or the corresponding rRNAs. Several isRNA candidates can also interact with transcripts of transcription factors and small nucleolar RNAs (snoRNAs) involved in the regulation of rRNA expression. We propose that the isRNAs derived from intronic regions of ribosomal protein coding genes may regulate the biogenesis of the ribosome through a feed-forward loop, ensuring the coordinated regulation of the RNA and protein components of the ribosomal machinery. Ribosome biogenesis and activity are fine-tuned to the conditions in the cell by integrating nutritional signals, stress response and growth to ensure optimal fitness. The enigmatic introns of ribosomal proteins may prove to be a novel and vital link in this regulatory balancing act.

scholarly journals USP16 counteracts mono-ubiquitination of RPS27a and promotes maturation of the 40S ribosomal subunit

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Christian Montellese ◽  
Jasmin van den Heuvel ◽  
Caroline Ashiono ◽  
Kerstin Dörner ◽  
André Melnik ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Protein Synthesis ◽  
Ribosome Biogenesis ◽  
18S Rrna ◽  
Ribosomal Subunit ◽  
Rrna Processing ◽  
Ribosomal Subunits ◽  
Novel Proteins ◽  
40S Ribosomal Subunit ◽  
Final Maturation

Establishment of translational competence represents a decisive cytoplasmic step in the biogenesis of 40S ribosomal subunits. This involves final 18S rRNA processing and release of residual biogenesis factors, including the protein kinase RIOK1. To identify novel proteins promoting the final maturation of human 40S subunits, we characterized pre-ribosomal subunits trapped on RIOK1 by mass spectrometry, and identified the deubiquitinase USP16 among the captured factors. We demonstrate that USP16 constitutes a component of late cytoplasmic pre-40S subunits that promotes the removal of ubiquitin from an internal lysine of ribosomal protein RPS27a/eS31. USP16 deletion leads to late 40S subunit maturation defects, manifesting in incomplete processing of 18S rRNA and retarded recycling of late-acting ribosome biogenesis factors, revealing an unexpected contribution of USP16 to the ultimate step of 40S synthesis. Finally, ubiquitination of RPS27a appears to depend on active translation, pointing at a potential connection between 40S maturation and protein synthesis.

Tandem Cell‐Free Protein Synthesis as a Tool for Rapid Screening of Optimal Molecular Chaperones

2019 ◽  
Vol 14 (5) ◽  
pp. 1800523
Author(s):  
Hyeon‐Jung Yang ◽  
Kyung‐Ho Lee ◽  
Hye Jin Lim ◽  
Dong‐Myung Kim
Keyword(s):  
Protein Synthesis ◽  
Molecular Chaperones ◽  
Rapid Screening ◽  
Free Protein ◽  
Tandem Cell ◽  
Cell Free Protein Synthesis

scholarly journals The Complexity of Human Ribosome Biogenesis Revealed by Systematic Nucleolar Screening of Pre-rRNA Processing Factors

2013 ◽  
Vol 51 (4) ◽  
pp. 539-551 ◽  
Author(s):  
Lionel Tafforeau ◽  
Christiane Zorbas ◽  
Jean-Louis Langhendries ◽  
Sahra-Taylor Mullineux ◽  
Vassiliki Stamatopoulou ◽  
...  
Keyword(s):  
Ribosome Biogenesis ◽  
Rrna Processing ◽  
Processing Factors

scholarly journals Bop1 Is a Mouse WD40 Repeat Nucleolar Protein Involved in 28S and 5.8S rRNA Processing and 60S Ribosome Biogenesis

2000 ◽  
Vol 20 (15) ◽  
pp. 5516-5528 ◽  
Author(s):  
Žaklina Strezoska ◽  
Dimitri G. Pestov ◽  
Lester F. Lau
Keyword(s):  
Ribosome Biogenesis ◽  
Ribosomal Subunit ◽  
Weight Fraction ◽  
Rnase A ◽  
Mutant Form ◽  
Rrna Processing ◽  
Ribonucleoprotein Complexes ◽  
Nuclear Extracts ◽  
Mouse Tissues ◽  
Mouse Cells

ABSTRACT We have identified and characterized a novel mouse protein, Bop1, which contains WD40 repeats and is highly conserved through evolution. bop1 is ubiquitously expressed in all mouse tissues examined and is upregulated during mid-G1 in serum-stimulated fibroblasts. Immunofluorescence analysis shows that Bop1 is localized predominantly to the nucleolus. In sucrose density gradients, Bop1 from nuclear extracts cosediments with the 50S-80S ribonucleoprotein particles that contain the 32S rRNA precursor. RNase A treatment disrupts these particles and releases Bop1 into a low-molecular-weight fraction. A mutant form of Bop1, Bop1Δ, which lacks 231 amino acids in the N- terminus, is colocalized with wild-type Bop1 in the nucleolus and in ribonucleoprotein complexes. Expression of Bop1Δ leads to cell growth arrest in the G1phase and results in a specific inhibition of the synthesis of the 28S and 5.8S rRNAs without affecting 18S rRNA formation. Pulse-chase analyses show that Bop1Δ expression results in a partial inhibition in the conversion of the 36S to the 32S pre-rRNA and a complete inhibition of the processing of the 32S pre-rRNA to form the mature 28S and 5.8S rRNAs. Concomitant with these defects in rRNA processing, expression of Bop1Δ in mouse cells leads to a deficit in the cytosolic 60S ribosomal subunits. These studies thus identify Bop1 as a novel, nonribosomal mammalian protein that plays a key role in the formation of the mature 28S and 5.8S rRNAs and in the biogenesis of the 60S ribosomal subunit.

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