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Pathogenic mutations reveal a role of RECQ4 in mitochondrial RNA:DNA hybrid formation and resolution

The synthesis of mitochondrial DNA (mtDNA) is a complex process that involves the formation and resolution of unusual nucleic acid structures, such as RNA:DNA hybrids. However, little is known about the enzymes that regulate these processes. RECQ4 is a DNA replication factor important for mtDNA main...

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Autores principales: Chang, Chou-Wei, Xu, Xiaohua, Li, Min, Xin, Di, Ding, Lin, Wang, Ya-Ting, Liu, Yilun
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7552406/
https://www.ncbi.nlm.nih.gov/pubmed/33046774
http://dx.doi.org/10.1038/s41598-020-74095-9
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author Chang, Chou-Wei
Xu, Xiaohua
Li, Min
Xin, Di
Ding, Lin
Wang, Ya-Ting
Liu, Yilun
author_facet Chang, Chou-Wei
Xu, Xiaohua
Li, Min
Xin, Di
Ding, Lin
Wang, Ya-Ting
Liu, Yilun
author_sort Chang, Chou-Wei
collection PubMed
description The synthesis of mitochondrial DNA (mtDNA) is a complex process that involves the formation and resolution of unusual nucleic acid structures, such as RNA:DNA hybrids. However, little is known about the enzymes that regulate these processes. RECQ4 is a DNA replication factor important for mtDNA maintenance, and here, we unveil a role of human RECQ4 in regulating the formation and resolution of mitochondrial RNA:DNA hybrids. Mitochondrial membrane protein p32 can block mtDNA synthesis by restricting RECQ4 mitochondrial localization via protein–protein interaction. We found that the interaction with p32 was disrupted not only by the previously reported cancer-associated RECQ4 mutation, del(A420-A463), but also by a clinical mutation of the adjacent residue, P466L. Surprisingly, although P466L mutant was present in the mitochondria at greater levels, unlike del(A420-A463) mutant, it failed to enhance mtDNA synthesis due to the accumulation of RNA:DNA hybrids throughout the mtDNA. Biochemical analysis revealed that P466L mutation enhanced RECQ4 annealing activity to generate RNA:DNA hybrids at the same time reduced its unwinding activity to resolve this structure. Hence, P466L mutation led to a reduced efficiency in completing mtDNA synthesis due to unresolved RNA:DNA hybrids across mtDNA.
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spelling pubmed-75524062020-10-14 Pathogenic mutations reveal a role of RECQ4 in mitochondrial RNA:DNA hybrid formation and resolution Chang, Chou-Wei Xu, Xiaohua Li, Min Xin, Di Ding, Lin Wang, Ya-Ting Liu, Yilun Sci Rep Article The synthesis of mitochondrial DNA (mtDNA) is a complex process that involves the formation and resolution of unusual nucleic acid structures, such as RNA:DNA hybrids. However, little is known about the enzymes that regulate these processes. RECQ4 is a DNA replication factor important for mtDNA maintenance, and here, we unveil a role of human RECQ4 in regulating the formation and resolution of mitochondrial RNA:DNA hybrids. Mitochondrial membrane protein p32 can block mtDNA synthesis by restricting RECQ4 mitochondrial localization via protein–protein interaction. We found that the interaction with p32 was disrupted not only by the previously reported cancer-associated RECQ4 mutation, del(A420-A463), but also by a clinical mutation of the adjacent residue, P466L. Surprisingly, although P466L mutant was present in the mitochondria at greater levels, unlike del(A420-A463) mutant, it failed to enhance mtDNA synthesis due to the accumulation of RNA:DNA hybrids throughout the mtDNA. Biochemical analysis revealed that P466L mutation enhanced RECQ4 annealing activity to generate RNA:DNA hybrids at the same time reduced its unwinding activity to resolve this structure. Hence, P466L mutation led to a reduced efficiency in completing mtDNA synthesis due to unresolved RNA:DNA hybrids across mtDNA. Nature Publishing Group UK 2020-10-12 /pmc/articles/PMC7552406/ /pubmed/33046774 http://dx.doi.org/10.1038/s41598-020-74095-9 Text en © The Author(s) 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
spellingShingle Article
Chang, Chou-Wei
Xu, Xiaohua
Li, Min
Xin, Di
Ding, Lin
Wang, Ya-Ting
Liu, Yilun
Pathogenic mutations reveal a role of RECQ4 in mitochondrial RNA:DNA hybrid formation and resolution
title Pathogenic mutations reveal a role of RECQ4 in mitochondrial RNA:DNA hybrid formation and resolution
title_full Pathogenic mutations reveal a role of RECQ4 in mitochondrial RNA:DNA hybrid formation and resolution
title_fullStr Pathogenic mutations reveal a role of RECQ4 in mitochondrial RNA:DNA hybrid formation and resolution
title_full_unstemmed Pathogenic mutations reveal a role of RECQ4 in mitochondrial RNA:DNA hybrid formation and resolution
title_short Pathogenic mutations reveal a role of RECQ4 in mitochondrial RNA:DNA hybrid formation and resolution
title_sort pathogenic mutations reveal a role of recq4 in mitochondrial rna:dna hybrid formation and resolution
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7552406/
https://www.ncbi.nlm.nih.gov/pubmed/33046774
http://dx.doi.org/10.1038/s41598-020-74095-9
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