scholarly journals Efficient site-specific cleavage by RNase MRP requires interaction with two evolutionarily conserved mitochondrial RNA sequences.

1990 ◽  
Vol 10 (5) ◽  
pp. 2191-2201 ◽  
Author(s):  
J L Bennett ◽  
D A Clayton

RNase MRP is a site-specific endonuclease that processes primer mitochondrial RNA from the leading-strand origin of mitochondrial DNA replication. Using deletional analysis and saturation mutagenesis, we have determined the substrate requirements for cleavage by mouse mitochondrial RNase MRP. Two regions of sequence homology among vertebrate mitochondrial RNA primers, conserved sequence blocks II and III, were found to be critical for both efficient and accurate cleavage; a third region of sequence homology, conserved sequence block I, was dispensable. Analysis of insertion and deletion mutations within conserved sequence block II demonstrated that the specificity of RNase MRP accommodates the natural sequence heterogeneity of conserved sequence block II in vivo. Heterologous assays with human RNase MRP and mutated mouse mitochondrial RNA substrates indicated that sequences essential for substrate recognition are conserved between mammalian species.

1990 ◽  
Vol 10 (5) ◽  
pp. 2191-2201
Author(s):  
J L Bennett ◽  
D A Clayton

RNase MRP is a site-specific endonuclease that processes primer mitochondrial RNA from the leading-strand origin of mitochondrial DNA replication. Using deletional analysis and saturation mutagenesis, we have determined the substrate requirements for cleavage by mouse mitochondrial RNase MRP. Two regions of sequence homology among vertebrate mitochondrial RNA primers, conserved sequence blocks II and III, were found to be critical for both efficient and accurate cleavage; a third region of sequence homology, conserved sequence block I, was dispensable. Analysis of insertion and deletion mutations within conserved sequence block II demonstrated that the specificity of RNase MRP accommodates the natural sequence heterogeneity of conserved sequence block II in vivo. Heterologous assays with human RNase MRP and mutated mouse mitochondrial RNA substrates indicated that sequences essential for substrate recognition are conserved between mammalian species.


RNA ◽  
2015 ◽  
Vol 21 (10) ◽  
pp. 1781-1789 ◽  
Author(s):  
Anthony J. Szempruch ◽  
Rajarshi Choudhury ◽  
Zefeng Wang ◽  
Stephen L. Hajduk

2005 ◽  
Vol 33 (3) ◽  
pp. 479-481 ◽  
Author(s):  
S.C. Walker ◽  
T.V. Aspinall ◽  
J.M.B. Gordon ◽  
J.M. Avis

In yeast, RNase MRP (mitochondrial RNA processing), a ribonucleoprotein precursor rRNA processing enzyme, possesses one putatively catalytic RNA and ten protein subunits and is highly related to RNase P. Structural analysis of the MRP RNA provides data that closely match a previous secondary-structure model derived from phylogenetic analysis, with the exception of an additional stem. This stem occupies an equivalent position to the P7 stem of RNase P RNA and its inclusion confers on MRP RNA a greater similarity to the core P RNA structure. In vivo studies indicate that the P7-like stem can form, but is not a part of, the active enzyme structure. Stem formation would increase RNA stability in the absence of proteins and our alternative structure may be a valid intermediate species in RNase MRP assembly. Further ongoing studies of this enzyme reveal an extensive network of interactions between subunits and a probable central role for the Pop1, Pop4 and Pop7 subunits.


2004 ◽  
Vol 24 (3) ◽  
pp. 945-953 ◽  
Author(s):  
Tina Gill ◽  
Ti Cai ◽  
Jason Aulds ◽  
Sara Wierzbicki ◽  
Mark E. Schmitt

ABSTRACT RNase mitochondrial RNA processing (RNase MRP) mutants have been shown to have an exit-from-mitosis defect that is caused by an increase in CLB2 mRNA levels, leading to increased Clb2p (B-cyclin) levels and a resulting late anaphase delay. Here we describe the molecular defect behind this delay. CLB2 mRNA normally disappears rapidly as cells complete mitosis, but the level remains high in RNase MRP mutants. This is in direct contrast to other exit-from-mitosis mutants and is the result of an increase in CLB2 mRNA stability. We found that highly purified RNase MRP cleaved the 5′ untranslated region (UTR) of the CLB2 mRNA in several places in an in vitro assay. In vivo, we identified RNase MRP-dependent cleavage products on the CLB2 mRNA that closely matched in vitro products. Disposal of these products was dependent on the 5′→3′ exoribonuclease Xrn1 and not the exosome. Our results demonstrate that the endoribonuclease RNase MRP specifically cleaves the CLB2 mRNA in its 5′-UTR to allow rapid 5′ to 3′ degradation by the Xrn1 nuclease. Degradation of the CLB2 mRNA by the RNase MRP endonuclease provides a novel way to regulate the cell cycle that complements the protein degradation machinery. In addition, these results denote a new mechanism of mRNA degradation not seen before in the yeast Saccharomyces cerevisiae.


2000 ◽  
Author(s):  
Anne K. Kowal ◽  
Caroline Kohrer ◽  
Uttam L. RajBhandary

Cancers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 428
Author(s):  
Emma Renard ◽  
Estel Collado Camps ◽  
Coline Canovas ◽  
Annemarie Kip ◽  
Martin Gotthardt ◽  
...  

Variable domains of heavy chain only antibodies (VHHs) are valuable agents for application in tumor theranostics upon conjugation to both a diagnostic probe and a therapeutic compound. Here, we optimized site-specific conjugation of the chelator DTPA and the photosensitizer IRDye700DX to anti-epidermal growth factor receptor (EGFR) VHH 7D12, for applications in nuclear imaging and photodynamic therapy. 7D12 was site-specifically equipped with bimodal probe DTPA-tetrazine-IRDye700DX using the dichlorotetrazine conjugation platform. Binding, internalization and light-induced toxicity of DTPA-IRDye700DX-7D12 were determined using EGFR-overexpressing A431 cells. Finally, ex vivo biodistribution of DTPA-IRDye700DX-7D12 in A431 tumor-bearing mice was performed, and tumor homing was visualized with SPECT and fluorescence imaging. DTPA-IRDye700DX-7D12 was retrieved with a protein recovery of 43%, and a degree of labeling of 0.56. Spectral properties of the IRDye700DX were retained upon conjugation. 111In-labeled DTPA-IRDye700DX-7D12 bound specifically to A431 cells, and they were effectively killed upon illumination. DTPA-IRDye700DX-7D12 homed to A431 xenografts in vivo, and this could be visualized with both SPECT and fluorescence imaging. In conclusion, the dichlorotetrazine platform offers a feasible method for site-specific dual-labeling of VHH 7D12, retaining binding affinity and therapeutic efficacy. The flexibility of the described approach makes it easy to vary the nature of the probes for other combinations of diagnostic and therapeutic compounds.


2003 ◽  
Vol 71 (11) ◽  
pp. 6648-6652 ◽  
Author(s):  
Steven Giles ◽  
Charles Czuprynski

ABSTRACT In this study we found that serum inhibitory activity against Blastomyces dermatitidis was principally mediated by albumin. This was confirmed in experiments using albumin from several mammalian species. Analbuminemic rat serum did not inhibit B. dermatitidis growth in vivo; however, the addition of albumin restored inhibitory activity. Inhibitory activity does not require albumin domain III and appears to involve binding of a low-molecular-weight yeast-derived growth factor.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ryan Lusk ◽  
Evan Stene ◽  
Farnoush Banaei-Kashani ◽  
Boris Tabakoff ◽  
Katerina Kechris ◽  
...  

AbstractAnnotation of polyadenylation sites from short-read RNA sequencing alone is a challenging computational task. Other algorithms rooted in DNA sequence predict potential polyadenylation sites; however, in vivo expression of a particular site varies based on a myriad of conditions. Here, we introduce aptardi (alternative polyadenylation transcriptome analysis from RNA-Seq data and DNA sequence information), which leverages both DNA sequence and RNA sequencing in a machine learning paradigm to predict expressed polyadenylation sites. Specifically, as input aptardi takes DNA nucleotide sequence, genome-aligned RNA-Seq data, and an initial transcriptome. The program evaluates these initial transcripts to identify expressed polyadenylation sites in the biological sample and refines transcript 3′-ends accordingly. The average precision of the aptardi model is twice that of a standard transcriptome assembler. In particular, the recall of the aptardi model (the proportion of true polyadenylation sites detected by the algorithm) is improved by over three-fold. Also, the model—trained using the Human Brain Reference RNA commercial standard—performs well when applied to RNA-sequencing samples from different tissues and different mammalian species. Finally, aptardi’s input is simple to compile and its output is easily amenable to downstream analyses such as quantitation and differential expression.


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