scholarly journals Functional characterization of two variants in the mitochondrial topoisomerase gene TOP1MT that impact regulation of the mitochondrial genome

2021 ◽  
Author(s):  
Iman Al Khatib ◽  
Marina Kerr ◽  
Hongliang Zhang ◽  
Shar-yin N huang ◽  
Yves Pommier ◽  
...  
Keyword(s):  
Mitochondrial Genome ◽  
Functional Characterization ◽  
Mtdna Copy Number ◽  
Human Pathology ◽  
Steady State Levels ◽  
Mitochondrial Replication ◽  
The Many ◽  
Insight Into ◽  
Comprehensive Characterization

TOP1MT encodes a mitochondrial topoisomerase that is important for mtDNA regulation, and is involved in mitochondrial replication, transcription and translation. Two variants predicted to affect TOP1MT function (R199C and V338L) were identified by exome sequencing of a newborn with hypertrophic cardiomyopathy. As no pathogenic TOP1MT variants have been confirmed previously, we characterized these variants for their ability to rescue several TOP1MT functions in knockout cells. Consistent with a role for these TOP1MT variants contributing to the patient phenotype, comprehensive characterization suggests that both variants had impaired topoisomerase activity and demonstrates that neither variant was able to restore steady state levels of mitochondrial encoded proteins, nor reduced oxidative phosphorylation. However, the two variants behaved differently in some respects. While the R199C variant was better at restoring transcript levels, the V338L variant was able to restore mtDNA copy number and replication. These findings suggest that the different TOP1MT variants affect distinct TOP1MT functions. Altogether, these findings begin to provide insight into the many roles that TOP1MT plays in the maintenance and expression of the mitochondrial genome, and how impairments in this important protein may lead to human pathology.

scholarly journals Functional characterization of the human tRNA methyltransferases TRMT10A and TRMT10B

2020 ◽  
Vol 48 (11) ◽  
pp. 6157-6169 ◽  
Author(s):  
Elisa Vilardo ◽  
Fabian Amman ◽  
Ursula Toth ◽  
Annika Kotter ◽  
Mark Helm ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Steady State ◽  
Human Genome ◽  
Functional Significance ◽  
Functional Characterization ◽  
Trna Methyltransferase ◽  
Steady State Levels

Abstract The TRM10 family of methyltransferases is responsible for the N1-methylation of purines at position 9 of tRNAs in Archaea and Eukarya. The human genome encodes three TRM10-type enzymes, of which only the mitochondrial TRMT10C was previously characterized in detail, whereas the functional significance of the two presumably nuclear enzymes TRMT10A and TRMT10B remained unexplained. Here we show that TRMT10A is m1G9-specific and methylates a subset of nuclear-encoded tRNAs, whilst TRMT10B is the first m1A9-specific tRNA methyltransferase found in eukaryotes and is responsible for the modification of a single nuclear-encoded tRNA. Furthermore, we show that the lack of G9 methylation causes a decrease in the steady-state levels of the initiator tRNAiMet-CAT and an alteration in its further post-transcriptional modification. Our work finally clarifies the function of TRMT10A and TRMT10B in vivo and provides evidence that the loss of TRMT10A affects the pool of cytosolic tRNAs required for protein synthesis.

scholarly journals Structural and functional characterization of mouse U7 small nuclear RNA active in 3' processing of histone pre-mRNA.

1988 ◽  
Vol 8 (4) ◽  
pp. 1518-1524 ◽  
Author(s):  
D Soldati ◽  
D Schümperli
Keyword(s):  
Sea Urchin ◽  
Functional Characterization ◽  
Rnase H ◽  
Primer Extension ◽  
Small Nuclear Rna ◽  
Nuclear Rna ◽  
Processing Signal ◽  
Insight Into

Oligonucleotides derived from the spacer element of the histone RNA 3' processing signal were used to characterize mouse U7 small nuclear RNA (snRNA), i.e., the snRNA component active in 3' processing of histone pre-mRNA. Under RNase H conditions, such oligonucleotides inhibited the processing reaction, indicating the formation of a DNA-RNA hybrid with a functional ribonucleoprotein component. Moreover, these oligonucleotides hybridized to a single nuclear RNA species of approximately 65 nucleotides. The sequence of this RNA was determined by primer extension experiments and was found to bear several structural similarities with sea urchin U7 snRNA. The comparison of mouse and sea urchin U7 snRNA structures yields some further insight into the mechanism of histone RNA 3' processing.

Phylogenetic analysis of fungal aquaporins provides insight into their possible role in water transport of mycorrhizal associations

Botany ◽  
2013 ◽  
Vol 91 (8) ◽  
pp. 495-504 ◽  
Author(s):  
Hao Xu ◽  
Janice E.K. Cooke ◽  
Janusz J. Zwiazek
Keyword(s):  
Water Transport ◽  
Mycorrhizal Fungi ◽  
Functional Characterization ◽  
Arbuscular Mycorrhizal ◽  
Gene Families ◽  
Fungal Species ◽  
Comparative Genomic ◽  
Mycorrhizal Associations ◽  
Insight Into

In mycorrhizal associations, water transport properties of the fungal hyphae may have a profound effect on water transport of the host plant. The importance of aquaporins, water-transporting members of the major intrinsic protein (MIP) family, in facilitating water transport has been widely acknowledged and extensively studied in plants. However, until recently, relatively little was known about the structure, function, and regulation of fungal MIPs. The rapid increase in the number of sequenced fungal genomes, including Laccaria bicolor and other mycorrhizal fungi, has enabled functional and comparative genomic investigations to delineate the role that fungal MIPs play in mycorrhizal-facilitated plant water transport. Phylogenic analysis of 229 fungal MIPs from 88 species revealed that MIPs of mycorrhizal fungal species fall into four clusters delineated by functionally characterized fungal MIPs: the orthodox aquaporins, the aquaglyceroporins, the facultative fungal aquaporins, and the X intrinsic proteins. This comparative genomics analysis, together with in silico structural characterization of predicted MIPs and recently published functional characterization of MIPs from a small number of ectomycorrhizal and arbuscular mycorrhizal species, provide new insight into MIP gene families of mycorrhizal fungi and possible roles for fungal aquaporins in water relations of mycorrhizal plant–fungus symbioses.

scholarly journals Discovery and characterization of Hv1-type proton channels in reef-building corals.

2021 ◽  
Author(s):  
Gisela Rangel-Tescas ◽  
Cecilia Cervantes ◽  
Miguel A Cervantes-Rocha ◽  
Esteban Suarez-Delgado ◽  
Anastazia T Banaszak ◽  
...  
Keyword(s):  
Voltage Dependence ◽  
Ph Regulation ◽  
Functional Characterization ◽  
Gene Encoding ◽  
Proton Channels ◽  
Gating Model ◽  
Mechanistic Insight ◽  
Voltage Dependent ◽  
Insight Into

Voltage-dependent proton-permeable channels are membrane proteins mediating a number of important physiological functions. Here we report the presence of a gene encoding for Hv1 voltage-dependent, proton-permeable channels in two species of reef-building corals. We performed a characterization of their biophysical properties and found that these channels are fast-activating and modulated by the pH gradient in a manner that makes them interesting models for studying these processes more easily. We have also developed an allosteric gating model that provides mechanistic insight into the modulation of voltage-dependence by protons. This work also represents the first functional characterization of any ion channel in scleractinian corals. We discuss the implications of the presence of these channels in the membranes of coral cells in the calcification and pH regulation processes and possible consequences of ocean acidification related to the function of these channels.

Urine Proteomics Profiling and Functional Characterization of Knee Osteoarthritis Using iTRAQ Technology

2019 ◽  
Vol 51 (11) ◽  
pp. 735-740 ◽  
Author(s):  
Ke Xiao ◽  
Lingjia Yu ◽  
Lisi Zhu ◽  
Zhihong Wu ◽  
Xisheng Weng ◽  
...  
Keyword(s):  
Functional Characterization ◽  
Joint Function ◽  
Urine Protein ◽  
Western Blots ◽  
Urine Proteomics ◽  
Protein Levels ◽  
Mass Spectrometry Technology ◽  
Proteome Profile ◽  
Insight Into

AbstractOsteoarthritis (OA) is a degenerative chronic disease affecting the whole joint structures. With the increment in life expectancy and aging population, OA has become one of the largest socioeconomic burdens, associated with pain and loss of joint function. However, early laboratory tests of OA are still lacking. Therefore, new diagnostic tests for this disease are urgently needed. In this study, to gain an insight into the pathogenesis and the potential biomarkers of OA, we implemented a comparative urine proteomics study on OA patients and health people using iTRAQ-based mass spectrometry technology. Western blotting was used to validate the relative changes in urine protein levels for four of the identified proteins. We constructed a comprehensive urine proteome profile of the OA patients and identified 102 proteins differently changed in abundance. Forty-six proteins were upregulated and 56 proteins were significantly downregulated in OA patients. Furthermore, the proteins, COL-4, MMP9, adiponectin, and BBOX1 were validated through Western blots, which can serve as valuable candidate biomarkers and help to illustrate the pathogenesis of OA. These findings may provide clues for promising biomarkers for the early diagnosis and also offer a theoretical basis for the early treatment of OA.

scholarly journals Functional characterization of tlmH in Streptoalloteichus hindustanus E465-94 ATCC 31158 unveiling new insight into tallysomycinbiosynthesis and affording a novel bleomycin analog

2010 ◽  
Vol 6 (2) ◽  
pp. 349-356 ◽  
Author(s):  
Meifeng Tao ◽  
Liyan Wang ◽  
Evelyn Wendt-Pienkowski ◽  
Ningning Zhang ◽  
Dong Yang ◽  
...  
Keyword(s):  
Functional Characterization ◽  
Insight Into

scholarly journals Genome-wide identification and characterization of the ALOG gene family in Petunia

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Feng Chen ◽  
Qin Zhou ◽  
Lan Wu ◽  
Fei Li ◽  
Baojun Liu ◽  
...  
Keyword(s):  
Gene Family ◽  
Expression Patterns ◽  
Functional Characterization ◽  
Reproductive Organs ◽  
Genome Wide ◽  
Domain Of Unknown Function ◽  
Intron Structure ◽  
Identification And Characterization ◽  
Insight Into

Abstract Background The ALOG (Arabidopsis LSH1 and Oryza G1) family of proteins, namely DUF640 (domain of unknown function 640) domain proteins, were found in land plants. Functional characterization of a few ALOG members in model plants such as Arabidopsis and rice suggested they play important regulatory roles in plant development. The information about its evolution, however, is largely limited, and there was no any report on the ALOG genes in Petunia, an important ornamental species. Results The ALOG genes were identified in four species of Petunia including P. axillaris, P. inflata, P. integrifolia, and P. exserta based on the genome and/or transcriptome databases, which were further confirmed by cloning from P. hybrida ‘W115’ (Mitchel diploid), a popular laboratorial petunia line susceptible to genetic transformation. Phylogenetic analysis indicated that Petunia ALOG genes (named as LSHs according to their closest Arabidopsis homologs) were grouped into four clades, which can be further divided into eight groups, and similar exon-intron structure and motifs are reflected in the same group. The PhLSH genes of hybrid petunia ‘W115’ were mainly derived from P. axillaris. The qPCR analysis revealed distinct spatial expression patterns among them suggesting potentially functional diversification. Moreover, over-expressing PhLSH7a and PhLSH7b in Arabidopsis uncovered their functions in the development of both vegetative and reproductive organs. Conclusions Petunia genome includes 11 ALOG genes that can be divided into eight distinct groups, and they also show different expression patterns. Among these genes, PhLSH7b and PhLSH7a play significant roles in plant growth and development, especially in fruit development. Our results provide new insight into the evolution of ALOG gene family and have laid a good foundation for the study of petunia LSH gene in the future.

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