Faculty Opinions recommendation of RNA chaperones stimulate formation and yield of the U3 snoRNA-Pre-rRNA duplexes needed for eukaryotic ribosome biogenesis.

In eukaryotic ribosome biogenesis, U3 snoRNA base pairs with the pre-rRNA to promote its processing. However, U3 must be removed to allow folding of the central pseudoknot, a key feature of the small subunit. Previously, we showed that the DEAH/RHA RNA helicase Dhr1 dislodges U3 from the pre-rRNA.DHR1can be linked toUTP14, encoding an essential protein of the preribosome, through genetic interactions with the rRNA methyltransferase Bud23. Here, we report that Utp14 regulates Dhr1. Mutations within a discrete region of Utp14 reduced interaction with Dhr1 that correlated with reduced function of Utp14. These mutants accumulated Dhr1 and U3 in a pre-40S particle, mimicking a helicase-inactive Dhr1 mutant. This similarity in the phenotypes led us to propose that Utp14 activates Dhr1. Indeed, Utp14 formed a complex with Dhr1 and stimulated its unwinding activityin vitro. Moreover, theutp14mutants that mimicked a catalytically inactivedhr1mutantin vivoshowed reduced stimulation of unwinding activityin vitro. Dhr1 binding to the preribosome was substantially reduced only when both Utp14 and Bud23 were depleted. Thus, Utp14 is bifunctional; together with Bud23, it is needed for stable interaction of Dhr1 with the preribosome, and Utp14 activates Dhr1 to dislodge U3.

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UtpA and UtpB chaperone nascent pre-ribosomal RNA and U3 snoRNA to initiate eukaryotic ribosome assembly

Nature Communications ◽

10.1038/ncomms12090 ◽

2016 ◽

Vol 7 (1) ◽

Cited By ~ 32

Author(s):

Mirjam Hunziker ◽

Jonas Barandun ◽

Elisabeth Petfalski ◽

Dongyan Tan ◽

Clémentine Delan-Forino ◽

...

Keyword(s):

Ribosomal Rna ◽

Ribosome Assembly ◽

Eukaryotic Ribosome ◽

U3 Snorna

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Identification of Genes That Function in the Biogenesis and Localization of Small Nucleolar RNAs in Saccharomyces cerevisiae

Molecular and Cellular Biology ◽

10.1128/mcb.01115-07 ◽

2008 ◽

Vol 28 (11) ◽

pp. 3686-3699 ◽

Cited By ~ 13

Author(s):

Hui Qiu ◽

Julia Eifert ◽

Ludivine Wacheul ◽

Marc Thiry ◽

Adam C. Berger ◽

...

Keyword(s):

Saccharomyces Cerevisiae ◽

Ribosome Biogenesis ◽

Large Scale ◽

Cajal Body ◽

Temperature Sensitive ◽

Small Nucleolar Rnas ◽

Animal Cells ◽

U3 Snorna ◽

Genes Encoding ◽

Nucleolar Rnas

ABSTRACT Small nucleolar RNAs (snoRNAs) orchestrate the modification and cleavage of pre-rRNA and are essential for ribosome biogenesis. Recent data suggest that after nucleoplasmic synthesis, snoRNAs transiently localize to the Cajal body (in plant and animal cells) or the homologous nucleolar body (in budding yeast) for maturation and assembly into snoRNPs prior to accumulation in their primary functional site, the nucleolus. However, little is known about the trans-acting factors important for the intranuclear trafficking and nucleolar localization of snoRNAs. Here, we describe a large-scale genetic screen to identify proteins important for snoRNA transport in Saccharomyces cerevisiae. We performed fluorescence in situ hybridization analysis to visualize U3 snoRNA localization in a collection of temperature-sensitive yeast mutants. We have identified Nop4, Prp21, Tao3, Sec14, and Htl1 as proteins important for the proper localization of U3 snoRNA. Mutations in genes encoding these proteins lead to specific defects in the targeting or retention of the snoRNA to either the nucleolar body or the nucleolus. Additional characterization of the mutants revealed impairment in specific steps of U3 snoRNA processing, demonstrating that snoRNA maturation and trafficking are linked processes.

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A network of assembly factors is involved in remodeling rRNA elements during preribosome maturation

The Journal of Cell Biology ◽

10.1083/jcb.201408111 ◽

2014 ◽

Vol 207 (4) ◽

pp. 481-498 ◽

Cited By ~ 35

Author(s):

Jochen Baßler ◽

Helge Paternoga ◽

Iris Holdermann ◽

Matthias Thoms ◽

Sander Granneman ◽

...

Keyword(s):

Ribosomal Rna ◽

Ribosome Biogenesis ◽

Ribosome Assembly ◽

Functional Importance ◽

Peptidyl Transferase ◽

Peptidyl Transferase Center ◽

Eukaryotic Ribosome ◽

Assembly Factors

Eukaryotic ribosome biogenesis involves ∼200 assembly factors, but how these contribute to ribosome maturation is poorly understood. Here, we identify a network of factors on the nascent 60S subunit that actively remodels preribosome structure. At its hub is Rsa4, a direct substrate of the force-generating ATPase Rea1. We show that Rsa4 is connected to the central protuberance by binding to Rpl5 and to ribosomal RNA (rRNA) helix 89 of the nascent peptidyl transferase center (PTC) through Nsa2. Importantly, Nsa2 binds to helix 89 before relocation of helix 89 to the PTC. Structure-based mutations of these factors reveal the functional importance of their interactions for ribosome assembly. Thus, Rsa4 is held tightly in the preribosome and can serve as a “distribution box,” transmitting remodeling energy from Rea1 into the developing ribosome. We suggest that a relay-like factor network coupled to a mechano-enzyme is strategically positioned to relocate rRNA elements during ribosome maturation.

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U3 snoRNA promoter reflects the RNA’s function in ribosome biogenesis

Current Genetics ◽

10.1007/s00294-008-0210-1 ◽

2008 ◽

Vol 54 (4) ◽

pp. 175-184 ◽

Cited By ~ 10

Author(s):

Sadeq Nabavi ◽

Ross N. Nazar

Keyword(s):

Ribosome Biogenesis ◽

U3 Snorna

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Inhibiting eukaryotic ribosome biogenesis: Mining new tools for basic research and medical applications

Microbial Cell ◽

10.15698/mic2019.10.695 ◽

2019 ◽

Vol 6 (10) ◽

pp. 491-493

Author(s):

Lisa Kofler ◽

Michael Prattes ◽

Helmut Bergler

Keyword(s):

Ribosome Biogenesis ◽

Basic Research ◽

Medical Applications ◽

Eukaryotic Ribosome

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Role of Pre-rRNA Base Pairing and 80S Complex Formation in Subnucleolar Localization of the U3 snoRNP

Molecular and Cellular Biology ◽

10.1128/mcb.24.19.8600-8610.2004 ◽

2004 ◽

Vol 24 (19) ◽

pp. 8600-8610 ◽

Cited By ~ 33

Author(s):

Sander Granneman ◽

Judith Vogelzangs ◽

Reinhard Lührmann ◽

Walther J. van Venrooij ◽

Ger J. M. Pruijn ◽

...

Keyword(s):

Complex Formation ◽

Ribosome Biogenesis ◽

Specific Protein ◽

Direct Result ◽

Rrna Processing ◽

Base Pairing ◽

Active Involvement ◽

U3 Snorna ◽

Fibrillar Component

ABSTRACT In the nucleolus the U3 snoRNA is recruited to the 80S pre-rRNA processing complex in the dense fibrillar component (DFC). The U3 snoRNA is found throughout the nucleolus and has been proposed to move with the preribosomes to the granular component (GC). In contrast, the localization of other RNAs, such as the U8 snoRNA, is restricted to the DFC. Here we show that the incorporation of the U3 snoRNA into the 80S processing complex is not dependent on pre-rRNA base pairing sequences but requires the B/C motif, a U3-specific protein-binding element. We also show that the binding of Mpp10 to the 80S U3 complex is dependent on sequences within the U3 snoRNA that base pair with the pre-rRNA adjacent to the initial cleavage site. Furthermore, mutations that inhibit 80S complex formation and/or the association of Mpp10 result in retention of the U3 snoRNA in the DFC. From this we propose that the GC localization of the U3 snoRNA is a direct result of its active involvement in the initial steps of ribosome biogenesis.

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