scholarly journals Structural insight into precursor ribosomal RNA processing by ribonuclease MRP

Science ◽  
2020 ◽  
Vol 369 (6504) ◽  
pp. 656-663 ◽  
Author(s):  
Pengfei Lan ◽  
Bin Zhou ◽  
Ming Tan ◽  
Shaobai Li ◽  
Mi Cao ◽  
...  
Keyword(s):  
Ribosomal Rna ◽  
Rna Processing ◽  
Cell Cycle Regulation ◽  
Consensus Sequence ◽  
Rrna Processing ◽  
Rnase Mrp ◽  
Cryo Electron Microscopy ◽  
Ribosomal Rna Processing ◽  
Cycle Regulation ◽  
Insight Into

Ribonuclease (RNase) MRP is a conserved eukaryotic ribonucleoprotein complex that plays essential roles in precursor ribosomal RNA (pre-rRNA) processing and cell cycle regulation. In contrast to RNase P, which selectively cleaves transfer RNA–like substrates, it has remained a mystery how RNase MRP recognizes its diverse substrates. To address this question, we determined cryo–electron microscopy structures of Saccharomyces cerevisiae RNase MRP alone and in complex with a fragment of pre-rRNA. These structures and the results of biochemical studies reveal that coevolution of both protein and RNA subunits has transformed RNase MRP into a distinct ribonuclease that processes single-stranded RNAs by recognizing a short, loosely defined consensus sequence. This broad substrate specificity suggests that RNase MRP may have myriad yet unrecognized substrates that could play important roles in various cellular contexts.

scholarly journals Both endonucleolytic and exonucleolytic cleavage mediate ITS1 removal during human ribosomal RNA processing

2013 ◽  
Vol 200 (5) ◽  
pp. 577-588 ◽  
Author(s):  
Katherine E. Sloan ◽  
Sandy Mattijssen ◽  
Simon Lebaron ◽  
David Tollervey ◽  
Ger J.M. Pruijn ◽  
...  
Keyword(s):  
Ribosomal Rna ◽  
Rna Processing ◽  
Large Subunit ◽  
Genetic Diseases ◽  
Evolutionary Conservation ◽  
Rrna Processing ◽  
Ribosomal Subunits ◽  
Important Pathway ◽  
Ribosomal Rna Processing ◽  
Insight Into

Human ribosome production is up-regulated during tumorogenesis and is defective in many genetic diseases (ribosomopathies). We have undertaken a detailed analysis of human precursor ribosomal RNA (pre-rRNA) processing because surprisingly little is known about this important pathway. Processing in internal transcribed spacer 1 (ITS1) is a key step that separates the rRNA components of the large and small ribosomal subunits. We report that this was initiated by endonuclease cleavage, which required large subunit biogenesis factors. This was followed by 3′ to 5′ exonucleolytic processing by RRP6 and the exosome, an enzyme complex not previously linked to ITS1 removal. In contrast, RNA interference–mediated knockdown of the endoribonuclease MRP did not result in a clear defect in ITS1 processing. Despite the apparently high evolutionary conservation of the pre-rRNA processing pathway and ribosome synthesis factors, each of these features of human ITS1 processing is distinct from those in budding yeast. These results also provide significant insight into the links between ribosomopathies and ribosome production in human cells.

scholarly journals A conserved RNA degradation complex required for spreading and epigenetic inheritance of heterochromatin

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Gergana Shipkovenska ◽  
Alexander Durango ◽  
Marian Kalocsay ◽  
Steven P Gygi ◽  
Danesh Moazed
Keyword(s):  
Ribosomal Rna ◽  
Rna Processing ◽  
Histone H3 ◽  
Epigenetic Inheritance ◽  
Rna Degradation ◽  
Heterochromatin Formation ◽  
Polynucleotide Kinase ◽  
Ribosomal Rna Processing ◽  
Formation System ◽  
Insight Into

Heterochromatic domains containing histone H3 lysine 9 methylation (H3K9me) can be epigenetically inherited independently of underlying DNA sequence. To gain insight into the mechanisms that mediate epigenetic inheritance, we used a Schizosaccharomyces pombe inducible heterochromatin formation system to perform a genetic screen for mutations that abolish heterochromatin inheritance without affecting its establishment. We identified mutations in several pathways, including the conserved and essential Rix1-associated complex (henceforth the rixosome), which contains RNA endonuclease and polynucleotide kinase activities with known roles in ribosomal RNA processing. We show that the rixosome is required for spreading and epigenetic inheritance of heterochromatin in fission yeast. Viable rixosome mutations that disrupt its association with Swi6/HP1 fail to localize to heterochromatin, lead to accumulation of heterochromatic RNAs, and block spreading of H3K9me and silencing into actively transcribed regions. These findings reveal a new pathway for degradation of heterochromatic RNAs with essential roles in heterochromatin spreading and inheritance.

Adenovirus infection retards ribosomal RNA processing

1989 ◽  
Vol 138 (1) ◽  
pp. 205-207 ◽  
Author(s):  
Susan H. Lawler ◽  
Robert W. Jones ◽  
Brian P. Eliceiri ◽  
George L. Eliceiri
Keyword(s):  
Ribosomal Rna ◽  
Rna Processing ◽  
Adenovirus Infection ◽  
Ribosomal Rna Processing

Developmental expression of fibrillarin and U3 snRNA in Xenopus laevis

Development ◽  
1991 ◽  
Vol 112 (1) ◽  
pp. 317-326
Author(s):  
M. Caizergues-Ferrer ◽  
C. Mathieu ◽  
P. Mariottini ◽  
F. Amalric ◽  
F. Amaldi
Keyword(s):  
Ribosomal Rna ◽  
Rna Processing ◽  
Protein Detection ◽  
Developmental Expression ◽  
Oocyte Growth ◽  
Small Nuclear Ribonucleoprotein ◽  
Hybridization Probes ◽  
Ribosomal Rna Processing ◽  
Protein Components ◽  
Nuclear Ribonucleoprotein

Fibrillarin is one of the protein components that together with U3 snRNA constitute the U3 snRNP, a small nuclear ribonucleoprotein particle involved in ribosomal RNA processing in eucaryotic cells. Using an antifibrillarin antiserum for protein detection and a fibrillarin cDNA and a synthetic oligonucleotide complementary to U3 snRNA as hybridization probes, the expression of these two components has been studied during Xenopus development. Fibrillarin mRNA is accumulated early in oogenesis, like many other messengers, and translated during oocyte growth. Fibrillarin protein is thus progressively accumulated throughout oogenesis to be assembled with U3 snRNA and used for ribosome production in the amplified nucleoli. After fertilization, the amount of U3 snRNA decreases while the maternally accumulated fibrillarin mRNA is maintained and utilized to produce more protein. After the mid-blastula transition, stored fibrillarin is assembled with newly synthesized U3 snRNA and becomes localized in the prenucleolar bodies and reforming nucleoli.

scholarly journals Epigenetic Regulation of Apoptosis and Cell Cycle in Osteosarcoma

Sarcoma ◽  
2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Krithi Rao-Bindal ◽  
Eugenie S. Kleinerman
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Regulation ◽  
Molecular Mechanisms ◽  
Genetic Mutations ◽  
Epigenetic Mechanisms ◽  
Epigenetic Alterations ◽  
Novel Therapeutic Strategies ◽  
Cycle Regulation ◽  
Insight Into

The role of genetic mutations in the development of osteosarcoma, such as alterations in p53 and Rb, is well understood. However, the significance of epigenetic mechanisms in the progression of osteosarcoma remains unclear and is increasingly being investigated. Recent evidence suggests that epigenetic alterations such as methylation and histone modifications of genes involved in cell cycle regulation and apoptosis may contribute to the pathogenesis of this tumor. Importantly, understanding the molecular mechanisms of regulation of these pathways may give insight into novel therapeutic strategies for patients with osteosarcoma. This paper serves to summarize the described epigenetic mechanisms in the tumorigenesis of osteosarcoma, specifically those pertaining to apoptosis and cell cycle regulation.

Defect in pre-ribosomal RNA processing is involved in myeloid leukemogenesis

2015 ◽  
Vol 43 (9) ◽  
pp. S78
Author(s):  
Hirotaka Matsui ◽  
Akinori Kanai ◽  
Akiko Nagamachi ◽  
Moe Okuno ◽  
Toshiya Inaba
Keyword(s):  
Ribosomal Rna ◽  
Rna Processing ◽  
Ribosomal Rna Processing

scholarly journals The 18S rRNA dimethylase Dim1p is required for pre-ribosomal RNA processing in yeast.

1995 ◽  
Vol 9 (20) ◽  
pp. 2470-2481 ◽  
Author(s):  
D Lafontaine ◽  
J Vandenhaute ◽  
D Tollervey
Keyword(s):  
Ribosomal Rna ◽  
Rna Processing ◽  
18S Rrna ◽  
Ribosomal Rna Processing
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