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Type: Journal article
Title: Modulation of mitochondrial DNA copy number in a model of glioblastoma induces changes to DNA methylation and gene expression of the nuclear genome in tumours
Author: Sun, X.
St John, J.C.
Citation: Epigenetics & chromatin, 2018; 11(1):53
Publisher: BMC
Issue Date: 2018
ISSN: 1756-8935
Statement of
Xin Sun and Justin C. St John
Abstract: BACKGROUND:There are multiple copies of mitochondrial DNA (mtDNA) present in each cell type, and they are strictly regulated in a cell-specific manner by a group of nuclear-encoded mtDNA-specific replication factors. This strict regulation of mtDNA copy number is mediated by cell-specific DNA methylation of these replication factors. Glioblastoma multiforme, HSR-GBM1, cells are hyper-methylated and maintain low mtDNA copy number to support their tumorigenic status. We have previously shown that when HSR-GBM1 cells with 50% of their original mtDNA content were inoculated into mice, tumours grew more aggressively than non-depleted cells. However, when the cells possessed only 3% and 0.2% of their original mtDNA content, tumour formation was less frequent and the initiation of tumorigenesis was significantly delayed. Importantly, the process of tumorigenesis was dependent on mtDNA copy number being restored to pre-depletion levels. RESULTS:By performing whole genome MeDIP-Seq and RNA-Seq on tumours generated from cells possessing 100%, 50%, 0.3% and 0.2% of their original mtDNA content, we determined that restoration of mtDNA copy number caused significant changes to both the nuclear methylome and its transcriptome for each tumour type. The affected genes were specifically associated with gene networks and pathways involving behaviour, nervous system development, cell differentiation and regulation of transcription and cellular processes. The mtDNA-specific replication factors were also modulated. CONCLUSIONS:Our results highlight the bidirectional control of the nuclear and mitochondrial genomes through modulation of DNA methylation to control mtDNA copy number, which, in turn, modulates nuclear gene expression during tumorigenesis.
Keywords: Mitochondrial DNA, DNA methylation; gene expression; tumorigenesis, POLG
Rights: © The Author(s) 2018. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creat iveco mmons .org/licen ses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creat iveco mmons .org/ publi cdoma in/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
RMID: 0030112254
DOI: 10.1186/s13072-018-0223-z
Appears in Collections:Genetics publications

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