scholarly journals Loss of Individual Mitochondrial Ribonuclease P Complex Proteins Differentially Affects Mitochondrial tRNA Processing In Vivo

2021 ◽  
Vol 22 (11) ◽  
pp. 6066
Author(s):  
Maithili Saoji ◽  
Aditya Sen ◽  
Rachel T. Cox
Keyword(s):  
Mitochondrial Dna ◽  
Mitochondrial Disease ◽  
Rnase P ◽  
Mitochondrial Proteins ◽  
Ribonuclease P ◽  
Mitochondrial Trna ◽  
Mt Dna ◽  
Trna Processing ◽  
Made In

Over a thousand nucleus-encoded mitochondrial proteins are imported from the cytoplasm; however, mitochondrial (mt) DNA encodes for a small number of critical proteins and the entire suite of mt:tRNAs responsible for translating these proteins. Mitochondrial RNase P (mtRNase P) is a three-protein complex responsible for cleaving and processing the 5′-end of mt:tRNAs. Mutations in any of the three proteins can cause mitochondrial disease, as well as mutations in mitochondrial DNA. Great strides have been made in understanding the enzymology of mtRNase P; however, how the loss of each protein causes mitochondrial dysfunction and abnormal mt:tRNA processing in vivo has not been examined in detail. Here, we used Drosophila genetics to selectively remove each member of the complex in order to assess their specific contributions to mt:tRNA cleavage. Using this powerful model, we find differential effects on cleavage depending on which complex member is lost and which mt:tRNA is being processed. These data revealed in vivo subtleties of mtRNase P function that could improve understanding of human diseases.

scholarly journals Interplay between substrate recognition, 5’ end tRNA processing and methylation activity of human mitochondrial RNase P

2018 ◽  
Author(s):  
Agnes Karasik ◽  
Carol A. Fierke ◽  
Markos Koutmos
Keyword(s):  
Mitochondrial Diseases ◽  
Protein S ◽  
Rnase P ◽  
Ribonuclease P ◽  
Mitochondrial Rna ◽  
P Protein ◽  
Adenosyl Methionine ◽  
Methylation Activity

ABSTRACTHuman mitochondrial ribonuclease P (mtRNase P) is an essential three protein complex that catalyzes the 5’ end maturation of mitochondrial precursor tRNAs (pre-tRNAs). MRPP3 (Mitochondrial RNase P Protein 3), a protein-only RNase P (PRORP), is the nuclease component of the mtRNase P complex and requires a two-protein S-adenosyl methionine (SAM)-dependent methyltransferase MRPP1/2 sub-complex to function. Dysfunction of mtRNase P is linked to several human mitochondrial diseases, such as mitochondrial myopathies. Despite its central role in mitochondrial RNA processing, little is known about how the protein subunits of mtRNase P function synergistically. Here we use purified mtRNase P to demonstrate that mtRNase P recognizes, cleaves, and methylates some, but not all, mitochondrial pre-tRNAs in vitro. Additionally, mtRNase P does not process all mitochondrial pre-tRNAs uniformly, suggesting the possibility that some pre-tRNAs require additional factors to be cleaved in vivo. Consistent with this, we found that addition of the MRPP1 co-factor SAM enhances the ability of mtRNase P to bind and cleave some mitochondrial pre-tRNAs. Furthermore, the presence of MRPP3 can enhance the methylation activity of MRPP1/2. Taken together, our data demonstrate that the subunits of mtRNase P work together to efficiently recognize, process and methylate human mitochondrial pre-tRNAs.

scholarly journals RNase P without RNA: Identification and Functional Reconstitution of the Human Mitochondrial tRNA Processing Enzyme

Cell ◽  
2008 ◽  
Vol 135 (3) ◽  
pp. 462-474 ◽  
Author(s):  
Johann Holzmann ◽  
Peter Frank ◽  
Esther Löffler ◽  
Keiryn L. Bennett ◽  
Christopher Gerner ◽  
...  
Keyword(s):  
Rnase P ◽  
Mitochondrial Trna ◽  
Trna Processing ◽  
Processing Enzyme

scholarly journals Proteasome Mutants, pre4-2 and ump1-2, Suppress the Essential Function but Not the Mitochondrial RNase P Function of the Saccharomyces cerevisiae Gene RPM2

Genetics ◽  
2000 ◽  
Vol 154 (3) ◽  
pp. 1013-1023 ◽  
Author(s):  
Mallory S Lutz ◽  
Steven R Ellis ◽  
Nancy C Martin
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Essential Gene ◽  
Carbon Sources ◽  
Growth Arrest ◽  
Nuclear Gene ◽  
Rnase P ◽  
20S Proteasome ◽  
Mitochondrial Trna ◽  
Additional Function ◽  
Trna Processing

Abstract The Saccharomyces cerevisiae nuclear gene RPM2 encodes a component of the mitochondrial tRNA-processing enzyme RNase P. Cells grown on fermentable carbon sources do not require mitochondrial tRNA processing activity, but still require RPM2, indicating an additional function for the Rpm2 protein. RPM2-null cells arrest after 25 generations on fermentable media. Spontaneous mutations that suppress arrest occur with a frequency of ~9 × 10−6. The resultant mutants do not grow on nonfermentable carbon sources. We identified two loci responsible for this suppression, which encode proteins that influence proteasome function or assembly. PRE4 is an essential gene encoding the β-7 subunit of the 20S proteasome core. A Val-to-Phe substitution within a highly conserved region of Pre4p that disrupts proteasome function suppresses the growth arrest of RPM2-null cells on fermentable media. The other locus, UMP1, encodes a chaperone involved in 20S proteasome assembly. A nonsense mutation in UMP1 also disrupts proteasome function and suppresses Δrpm2 growth arrest. In an RPM2 wild-type background, pre4-2 and ump1-2 strains fail to grow at restrictive temperatures on nonfermentable carbon sources. These data link proteasome activity with Rpm2p and mitochondrial function.

In Vitro and in Vivo Processing of Cyanelle tmRNA by RNase P

2001 ◽  
Vol 382 (10) ◽  
pp. 1421-1429 ◽  
Author(s):  
O. Gimple ◽  
A. Schön
Keyword(s):  
Rnase P ◽  
Ribonuclease P ◽  
Structure Model ◽  
Cyanophora Paradoxa ◽  
Secondary Structure Model ◽  
Precursor Molecule ◽  
Its Gene ◽  
Multicellular Organisms

Abstract Ribonuclease P, the ubiquitous endonuclease required for generating mature tRNA 5 ends, is a ribonucleoprotein in most organisms and organelles, with the exception of mitochondria and chloroplasts of multicellular organisms. The cyanelle of the primitive alga Cyanophora paradoxa is the only photosynthetic organelle where the ribonucleoprotein nature of this enzyme has been functionally proven. tmRNA is another highly structured RNA: it can be aminoacylated with alanine, which is then incorporated into a tag peptide encoded on the same RNA molecule. This dualfunction RNA has been found in bacteria, and its gene is also present in mitochondria and plastids from primitive organisms. Since nothing is known about the expression of this RNA in organelles, we have performed processing studies and determined the promoter of cyanelle pretmRNA. This RNA is transcribed as a precursor molecule in vivo. Synthetic transcripts of cyanelle pretmRNA, including or lacking the mature 3 CCAend, are efficiently and correctly processed in vitro by bacterial RNase P ribo and holoenzymes and by the homologous cyanelle RNase P. In addition to these experimental data, we propose a novel secondary structure model for this organellar tmRNA, which renders it more similar to its bacterial counterpart.

scholarly journals The Role of Mitochondrial DNA Mutations in Cardiovascular Diseases

2022 ◽  
Vol 23 (2) ◽  
pp. 952
Author(s):  
Siarhei A. Dabravolski ◽  
Victoria A. Khotina ◽  
Vasily N. Sukhorukov ◽  
Vladislav A. Kalmykov ◽  
Liudmila M. Mikhaleva ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Cardiovascular Diseases ◽  
Molecular Mechanisms ◽  
Mitochondrial Proteins ◽  
Mitochondrial Trna ◽  
Mtdna Mutations ◽  
Mitochondrial Dna Mutations ◽  
Dna Mutations ◽  
Artery Disease

Cardiovascular diseases (CVD) are one of the leading causes of morbidity and mortality worldwide. mtDNA (mitochondrial DNA) mutations are known to participate in the development and progression of some CVD. Moreover, specific types of mitochondria-mediated CVD have been discovered, such as MIEH (maternally inherited essential hypertension) and maternally inherited CHD (coronary heart disease). Maternally inherited mitochondrial CVD is caused by certain mutations in the mtDNA, which encode structural mitochondrial proteins and mitochondrial tRNA. In this review, we focus on recently identified mtDNA mutations associated with CVD (coronary artery disease and hypertension). Additionally, new data suggest the role of mtDNA mutations in Brugada syndrome and ischemic stroke, which before were considered only as a result of mutations in nuclear genes. Moreover, we discuss the molecular mechanisms of mtDNA involvement in the development of the disease.

scholarly journals The Dynamic Network of RNP RNase P Subunits

2021 ◽  
Vol 22 (19) ◽  
pp. 10307
Author(s):  
Athanasios-Nasir Shaukat ◽  
Eleni G. Kaliatsi ◽  
Ilias Skeparnias ◽  
Constantinos Stathopoulos
Keyword(s):  
Dynamic Network ◽  
Rnase P ◽  
Ribonuclease P ◽  
Protein Subunit ◽  
Protein Subunits ◽  
Phosphodiester Bond ◽  
Cellular Processes ◽  
Protein Partners

Ribonuclease P (RNase P) is an important ribonucleoprotein (RNP), responsible for the maturation of the 5′ end of precursor tRNAs (pre-tRNAs). In all organisms, the cleavage activity of a single phosphodiester bond adjacent to the first nucleotide of the acceptor stem is indispensable for cell viability and lies within an essential catalytic RNA subunit. Although RNase P is a ribozyme, its kinetic efficiency in vivo, as well as its structural variability and complexity throughout evolution, requires the presence of one protein subunit in bacteria to several protein partners in archaea and eukaryotes. Moreover, the existence of protein-only RNase P (PRORP) enzymes in several organisms and organelles suggests a more complex evolutionary timeline than previously thought. Recent detailed structures of bacterial, archaeal, human and mitochondrial RNase P complexes suggest that, although apparently dissimilar enzymes, they all recognize pre-tRNAs through conserved interactions. Interestingly, individual protein subunits of the human nuclear and mitochondrial holoenzymes have additional functions and contribute to a dynamic network of elaborate interactions and cellular processes. Herein, we summarize the role of each RNase P subunit with a focus on the human nuclear RNP and its putative role in flawless gene expression in light of recent structural studies.

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