Primer retention owing to the absence of RNase H1 is catastrophic for mitochondrial DNA replication.

TitlePrimer retention owing to the absence of RNase H1 is catastrophic for mitochondrial DNA replication.
Publication TypeJournal Article
Year of Publication2015
AuthorsJ Holmes, B, Akman, G, Wood, SR, Sakhuja, K, Cerritelli, SM, Moss, C, Bowmaker, MR, Jacobs, HT, Crouch, RJ, Holt, IJ
JournalProc Natl Acad Sci U S A
Volume112
Issue30
Pagination9334-9
Date Published2015 Jul 28
ISSN1091-6490
KeywordsAnimals, Cell Line, DNA, DNA Primers, DNA Replication, DNA, Mitochondrial, Exons, Fibroblasts, Genotype, Homozygote, Mice, Mice, Knockout, Mitochondria, Nucleotides, Replication Origin, Ribonuclease H, RNA, RNA, Mitochondrial
Abstract

Encoding ribonuclease H1 (RNase H1) degrades RNA hybridized to DNA, and its function is essential for mitochondrial DNA maintenance in the developing mouse. Here we define the role of RNase H1 in mitochondrial DNA replication. Analysis of replicating mitochondrial DNA in embryonic fibroblasts lacking RNase H1 reveals retention of three primers in the major noncoding region (NCR) and one at the prominent lagging-strand initiation site termed Ori-L. Primer retention does not lead immediately to depletion, as the persistent RNA is fully incorporated in mitochondrial DNA. However, the retained primers present an obstacle to the mitochondrial DNA polymerase γ in subsequent rounds of replication and lead to the catastrophic generation of a double-strand break at the origin when the resulting gapped molecules are copied. Hence, the essential role of RNase H1 in mitochondrial DNA replication is the removal of primers at the origin of replication.

DOI10.1073/pnas.1503653112
Alternate JournalProc. Natl. Acad. Sci. U.S.A.
Citation Key10.1073/pnas.1503653112
PubMed ID26162680
PubMed Central IDPMC4522766
Grant ListMC_U105663140 / / Medical Research Council / United Kingdom
R01 GM031819 / GM / NIGMS NIH HHS / United States
GM31819 / GM / NIGMS NIH HHS / United States
/ / Intramural NIH HHS / United States