scholarly journals The RNA helicase Dbp7 promotes domain V/VI compaction and stabilization of inter-domain interactions during early 60S assembly

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Gerald Ryan R. Aquino ◽  
Philipp Hackert ◽  
Nicolai Krogh ◽  
Kuan-Ting Pan ◽  
Mariam Jaafar ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Ribosomal Protein ◽  
Ribosomal Proteins ◽  
Rna Helicase ◽  
Rna Helicases ◽  
Assembly Factors ◽  
Domain Interactions ◽  
Protein Dissociation ◽  
Peptidyltransferase Center ◽  
Domain V

AbstractEarly pre-60S ribosomal particles are poorly characterized, highly dynamic complexes that undergo extensive rRNA folding and compaction concomitant with assembly of ribosomal proteins and exchange of assembly factors. Pre-60S particles contain numerous RNA helicases, which are likely regulators of accurate and efficient formation of appropriate rRNA structures. Here we reveal binding of the RNA helicase Dbp7 to domain V/VI of early pre-60S particles in yeast and show that in the absence of this protein, dissociation of the Npa1 scaffolding complex, release of the snR190 folding chaperone, recruitment of the A3 cluster factors and binding of the ribosomal protein uL3 are impaired. uL3 is critical for formation of the peptidyltransferase center (PTC) and is responsible for stabilizing interactions between the 5′ and 3′ ends of the 25S, an essential pre-requisite for subsequent pre-60S maturation events. Highlighting the importance of pre-ribosome remodeling by Dbp7, our data suggest that in the absence of Dbp7 or its catalytic activity, early pre-ribosomal particles are targeted for degradation.

scholarly journals The DHX33 RNA Helicase Promotes mRNA Translation Initiation

2015 ◽  
Vol 35 (17) ◽  
pp. 2918-2931 ◽  
Author(s):  
Yandong Zhang ◽  
Jin You ◽  
Xingshun Wang ◽  
Jason Weber
Keyword(s):  
Translation Initiation ◽  
Ribosomal Proteins ◽  
Ribosome Biogenesis ◽  
Mrna Translation ◽  
Rna Helicase ◽  
Rna Helicases ◽  
80S Ribosome ◽  
Protein Levels ◽  
Cell Growth And Proliferation ◽  
Rna Complexes

DEAD/DEAH box RNA helicases play essential roles in numerous RNA metabolic processes, such as mRNA translation, pre-mRNA splicing, ribosome biogenesis, and double-stranded RNA sensing. Herein we show that a recently characterized DEAD/DEAH box RNA helicase, DHX33, promotes mRNA translation initiation. We isolated intact DHX33 protein/RNA complexes in cells and identified several ribosomal proteins, translation factors, and mRNAs. Reduction of DHX33 protein levels markedly reduced polyribosome formation and caused the global inhibition of mRNA translation that was rescued with wild-type DHX33 but not helicase-defective DHX33. Moreover, we observed an accumulation of mRNA complexes with the 80S ribosome in the absence of functional DHX33, consistent with a stalling in initiation, and DHX33 more preferentially promoted structured mRNA translation. We conclude that DHX33 functions to promote elongation-competent 80S ribosome assembly at the late stage of mRNA translation initiation. Our results reveal a newly recognized function of DHX33 in mRNA translation initiation, further solidifying its central role in promoting cell growth and proliferation.

scholarly journals The DEAH-box RNA helicase Dhr1 contains a remarkable carboxyl terminal domain essential for small ribosomal subunit biogenesis

2019 ◽  
Vol 47 (14) ◽  
pp. 7548-7563 ◽  
Author(s):  
Amlan Roychowdhury ◽  
Clément Joret ◽  
Gabrielle Bourgeois ◽  
Valérie Heurgué-Hamard ◽  
Denis L J Lafontaine ◽  
...  
Keyword(s):  
Ribosomal Proteins ◽  
Ribosome Biogenesis ◽  
Ribosomal Subunit ◽  
Rna Helicases ◽  
Range Interaction ◽  
Small Ribosomal Subunit ◽  
Terminal Domain ◽  
Carboxyl Terminal Domain ◽  
Assembly Factors ◽  
Carboxyl Terminal

Abstract Ribosome biogenesis is an essential process in all living cells, which entails countless highly sequential and dynamic structural reorganization events. These include formation of dozens RNA helices through Watson-Crick base-pairing within ribosomal RNAs (rRNAs) and between rRNAs and small nucleolar RNAs (snoRNAs), transient association of hundreds of proteinaceous assembly factors to nascent precursor (pre-)ribosomes, and stable assembly of ribosomal proteins. Unsurprisingly, the largest group of ribosome assembly factors are energy-consuming proteins (NTPases) including 25 RNA helicases in budding yeast. Among these, the DEAH-box Dhr1 is essential to displace the box C/D snoRNA U3 from the pre-rRNAs where it is bound in order to prevent premature formation of the central pseudoknot, a dramatic irreversible long-range interaction essential to the overall folding of the small ribosomal subunit. Here, we report the crystal structure of the Dhr1 helicase module, revealing the presence of a remarkable carboxyl-terminal domain essential for Dhr1 function in ribosome biogenesis in vivo and important for its interaction with its coactivator Utp14 in vitro. Furthermore, we report the functional consequences on ribosome biogenesis of DHX37 (human Dhr1) mutations found in patients suffering from microcephaly and other neurological diseases.

scholarly journals RNA Helicases from the DEA(D/H)-Box Family Contribute to Plant NMD Efficiency

2019 ◽  
Vol 61 (1) ◽  
pp. 144-157 ◽  
Author(s):  
Aleksandra Sulkowska ◽  
Andor Auber ◽  
Pawel J Sikorski ◽  
D�niel Silhavy ◽  
Mariann Auth ◽  
...  
Keyword(s):  
Ribosomal Proteins ◽  
Translation Termination ◽  
Affinity Purification ◽  
Rna Helicase ◽  
Inhibitory Effect ◽  
Rna Helicases ◽  
Initiation Factors ◽  
Functional Studies ◽  
Protein Levels ◽  
Transient Overexpression

Abstract Nonsense-mediated mRNA decay (NMD) is a conserved eukaryotic RNA surveillance mechanism that degrades aberrant mRNAs comprising a premature translation termination codon. The adenosine triphosphate (ATP)-dependent RNA helicase up-frameshift 1 (UPF1) is a major NMD factor in all studied organisms; however, the complexity of this mechanism has not been fully characterized in plants. To identify plant NMD factors, we analyzed UPF1-interacting proteins using tandem affinity purification coupled to mass spectrometry. Canonical members of the NMD pathway were found along with numerous NMD candidate factors, including conserved DEA(D/H)-box RNA helicase homologs of human DDX3, DDX5 and DDX6, translation initiation factors, ribosomal proteins and transport factors. Our functional studies revealed that depletion of DDX3 helicases enhances the accumulation of NMD target reporter mRNAs but does not result in increased protein levels. In contrast, silencing of DDX6 group leads to decreased accumulation of the NMD substrate. The inhibitory effect of DDX6-like helicases on NMD was confirmed by transient overexpression of RH12 helicase. These results indicate that DDX3 and DDX6 helicases in plants have a direct and opposing contribution to NMD and act as functional NMD factors.

scholarly journals A distinct assembly pathway of the human 39S late pre-mitoribosome

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jingdong Cheng ◽  
Otto Berninghausen ◽  
Roland Beckmann
Keyword(s):  
16S Rrna ◽  
Affinity Purification ◽  
Large Subunit ◽  
Assembly Pathway ◽  
Assembly Factors ◽  
Peptidyltransferase Center

AbstractAssembly of the mitoribosome is largely enigmatic and involves numerous assembly factors. Little is known about their function and the architectural transitions of the pre-ribosomal intermediates. Here, we solve cryo-EM structures of the human 39S large subunit pre-ribosomes, representing five distinct late states. Besides the MALSU1 complex used as bait for affinity purification, we identify several assembly factors, including the DDX28 helicase, MRM3, GTPBP10 and the NSUN4-mTERF4 complex, all of which keep the 16S rRNA in immature conformations. The late transitions mainly involve rRNA domains IV and V, which form the central protuberance, the intersubunit side and the peptidyltransferase center of the 39S subunit. Unexpectedly, we find deacylated tRNA in the ribosomal E-site, suggesting a role in 39S assembly. Taken together, our study provides an architectural inventory of the distinct late assembly phase of the human 39S mitoribosome.

scholarly journals Ubiquitin and Ubiquitin-Like Proteins and Domains in Ribosome Production and Function: Chance or Necessity?

2021 ◽  
Vol 22 (9) ◽  
pp. 4359
Author(s):  
Sara Martín-Villanueva ◽  
Gabriel Gutiérrez ◽  
Dieter Kressler ◽  
Jesús de la Cruz
Keyword(s):  
Ribosomal Proteins ◽  
Ribosome Biogenesis ◽  
Ribosome Assembly ◽  
Cellular Processes ◽  
Substrate Protein ◽  
Precursor Proteins ◽  
Assembly Factors ◽  
Ubiquitin Moiety ◽  
And Function

Ubiquitin is a small protein that is highly conserved throughout eukaryotes. It operates as a reversible post-translational modifier through a process known as ubiquitination, which involves the addition of one or several ubiquitin moieties to a substrate protein. These modifications mark proteins for proteasome-dependent degradation or alter their localization or activity in a variety of cellular processes. In most eukaryotes, ubiquitin is generated by the proteolytic cleavage of precursor proteins in which it is fused either to itself, constituting a polyubiquitin precursor, or as a single N-terminal moiety to ribosomal proteins, which are practically invariably eL40 and eS31. Herein, we summarize the contribution of the ubiquitin moiety within precursors of ribosomal proteins to ribosome biogenesis and function and discuss the biological relevance of having maintained the explicit fusion to eL40 and eS31 during evolution. There are other ubiquitin-like proteins, which also work as post-translational modifiers, among them the small ubiquitin-like modifier (SUMO). Both ubiquitin and SUMO are able to modify ribosome assembly factors and ribosomal proteins to regulate ribosome biogenesis and function. Strikingly, ubiquitin-like domains are also found within two ribosome assembly factors; hence, the functional role of these proteins will also be highlighted.

scholarly journals Association of the Cold Shock DEAD-Box RNA Helicase RhlE to the RNA Degradosome in Caulobacter crescentus

2017 ◽  
Vol 199 (13) ◽  
Author(s):  
Angel A. Aguirre ◽  
Alexandre M. Vicente ◽  
Steven W. Hardwick ◽  
Daniela M. Alvelos ◽  
Ricardo R. Mazzon ◽  
...  
Keyword(s):  
Low Temperature ◽  
Caulobacter Crescentus ◽  
Immunoblot Analysis ◽  
Rna Helicase ◽  
Rnase E ◽  
Rna Helicases ◽  
Content Type ◽  
Dead Box ◽  
Rna Degradosome ◽  
The Dead

ABSTRACT In diverse bacterial lineages, multienzyme assemblies have evolved that are central elements of RNA metabolism and RNA-mediated regulation. The aquatic Gram-negative bacterium Caulobacter crescentus, which has been a model system for studying the bacterial cell cycle, has an RNA degradosome assembly that is formed by the endoribonuclease RNase E and includes the DEAD-box RNA helicase RhlB. Immunoprecipitations of extracts from cells expressing an epitope-tagged RNase E reveal that RhlE, another member of the DEAD-box helicase family, associates with the degradosome at temperatures below those optimum for growth. Phenotype analyses of rhlE, rhlB, and rhlE rhlB mutant strains show that RhlE is important for cell fitness at low temperature and its role may not be substituted by RhlB. Transcriptional and translational fusions of rhlE to the lacZ reporter gene and immunoblot analysis of an epitope-tagged RhlE indicate that its expression is induced upon temperature decrease, mainly through posttranscriptional regulation. RNase E pulldown assays show that other proteins, including the transcription termination factor Rho, a second DEAD-box RNA helicase, and ribosomal protein S1, also associate with the degradosome at low temperature. The results suggest that the RNA degradosome assembly can be remodeled with environmental change to alter its repertoire of helicases and other accessory proteins. IMPORTANCE DEAD-box RNA helicases are often present in the RNA degradosome complex, helping unwind secondary structures to facilitate degradation. Caulobacter crescentus is an interesting organism to investigate degradosome remodeling with change in temperature, because it thrives in freshwater bodies and withstands low temperature. In this study, we show that at low temperature, the cold-induced DEAD-box RNA helicase RhlE is recruited to the RNA degradosome, along with other helicases and the Rho protein. RhlE is essential for bacterial fitness at low temperature, and its function may not be complemented by RhlB, although RhlE is able to complement for rhlB loss. These results suggest that RhlE has a specific role in the degradosome at low temperature, potentially improving adaptation to this condition.

The N-terminal Sequence of Ribosomal Protein L10 from the ArchaebacteriumHalobacterium marismortuiand its Relationship to Eubacterial Protein L6 and Other Ribosomal Proteins

1987 ◽  
Vol 368 (2) ◽  
pp. 921-926 ◽  
Author(s):  
Jan DIJK ◽  
Rudolf VAN DEN BROEK ◽  
Georgios NASIULAS ◽  
Alfred BECK ◽  
Richard REINHARDT ◽  
...  
Keyword(s):  
Ribosomal Protein ◽  
Ribosomal Proteins ◽  
Terminal Sequence

scholarly journals Halobacterium cutirubrum ribosomes. Properties of the ribosomal proteins and ribonucleic acid

1972 ◽  
Vol 130 (1) ◽  
pp. 103-110 ◽  
Author(s):  
L. P. Visentin ◽  
C. Chow ◽  
A. T. Matheson ◽  
M. Yaguchi ◽  
F. Rollin
Keyword(s):  
Ribosomal Protein ◽  
Ribosomal Proteins ◽  
Soluble Fraction ◽  
Ribosomal Subunit ◽  
23S Rrna ◽  
Core Particle ◽  
Fractionation Procedure ◽  
Additional Protein ◽  
70S Ribosome ◽  
Low Ionic Strength

1. The 30S ribosomal subunit of the extreme halophile Halobacterium cutirubrum is unstable and loses 75% of its ribosomal protein when the 70S ribosome is dissociated into the two subunits. A stable 30S subunit is obtained if the dissociation of the 70S particle is carried out in the presence of the soluble fraction. 2. A fractionation procedure was developed for the selective removal of groups of proteins from the 30S and 50S subunits. When the ribosomes, which are stable in 4m-K+ and 0.1m-Mg2+, were extracted with low-ionic-strength buffer 75–80% of the 30S proteins and 60–65% of the 50S proteins as well as the 5S rRNA were released. The proteins in this fraction are the most acidic of the H. cutirubrum ribosomal proteins. Further extraction with Li+–EDTA releases additional protein, leaving a core particle containing either 16S rRNA or 23S rRNA and about 5% of the total ribosomal protein. The amino acid composition, mobility on polyacrylamide gels at pH4.5 and 8.7, and the molecular-weight distribution of the various protein fractions were determined. 3. The s values of the rRNA are 5S, 16S and 23S. The C+G contents of the 16S and 23S rRNA were 56.1 and 58.8% respectively and these are higher than C+G contents of the corresponding Escherichia coli rRNA (53.8 and 54.1%).

scholarly journals The embryonic RNA helicase gene (ERH): a new member of the DEAD box family of RNA helicases

1995 ◽  
Vol 308 (3) ◽  
pp. 839-846 ◽  
Author(s):  
J Sowden ◽  
W Putt ◽  
K Morrison ◽  
R Beddington ◽  
Y Edwards
Keyword(s):  
Expression Profile ◽  
Sequence Similarity ◽  
Rna Helicase ◽  
Chromosome 1 ◽  
Rna Helicases ◽  
High Sequence Similarity ◽  
Dead Box ◽  
Isolation And Characterization ◽  
Helicase Gene ◽  
The Dead

DEAD box proteins share several highly conserved motifs including the characteristic Asp-Glu-Ala-Asp (D-E-A-D in the amino acid single-letter code) motif and have established or putative ATP-dependent RNA helicase activity. These proteins are implicated in a range of cellular processes that involve regulation of RNA function, including translation initiation, RNA splicing and ribosome assembly. Here we describe the isolation and characterization of an embryonic RNA helicase gene, ERH, which maps to mouse chromosome 1 and encodes a new member of the DEAD box family of proteins. The predicted ERH protein shows high sequence similarity to the testes-specific mouse PL10 and to the maternally acting Xenopus An3 helicase proteins. The ERH expression profile is similar, to that of An3, which localizes to the animal hemisphere of oocytes and is abundantly expressed in the embryo. ERH is expressed in oocytes and is a ubiquitous mRNA in the 9 days-post-conception embryo, and at later stages of development shows a more restricted pattern of expression in brain and kidney. The similarities in sequence and in expression profile suggest that ERH is the murine equivalent of the Xenopus An3 gene, and we propose that ERH plays a role in translational activation of mRNA in the oocyte and early embryo.

An intergenic G-rich region in Leishmania tarentolae kinetoplast maxicircle DNA is a pan-edited cryptogene encoding ribosomal protein S12

1992 ◽  
Vol 12 (1) ◽  
pp. 56-67
Author(s):  
D A Maslov ◽  
N R Sturm ◽  
B M Niner ◽  
E S Gruszynski ◽  
M Peris ◽  
...  
Keyword(s):  
Amino Acid ◽  
Ribosomal Protein ◽  
Ribosomal Proteins ◽  
Sequence Similarity ◽  
Rich Region ◽  
Leishmania Tarentolae ◽  
Significant Sequence Similarity ◽  
The Family ◽  
Intergenic Regions ◽  
Ribosomal Protein S12

Six short G-rich intergenic regions in the maxicircle of Leishmania tarentolae are conserved in location and polarity in two other kinetoplastid species. We show here that G-rich region 6 (G6) represents a pan-edited cryptogene which contains at least two domains edited independently in a 3'-to-5' manner connected by short unedited regions. In the completely edited RNA, 117 uridines are added at 49 sites and 32 uridines are deleted at 13 sites, creating a translated 85-amino-acid polypeptide. Similar polypeptides are probably encoded by pan-edited G6 transcripts in two other species. The G6 polypeptide has significant sequence similarity to the family of S12 ribosomal proteins. A minicircle-encoded gRNA overlaps 12 editing sites in G6 mRNA, and chimeric gRNA/mRNA molecules were shown to exist, in agreement with the transesterification model for editing.

Sign in / Sign up

Export Citation Format

Share Document