Biased incorporation of ribonucleotides on the mitochondrial L-strand accounts for apparent strand-asymmetric DNA replication.

TitleBiased incorporation of ribonucleotides on the mitochondrial L-strand accounts for apparent strand-asymmetric DNA replication.
Publication TypeJournal Article
Year of Publication2002
AuthorsYang, MYao, Bowmaker, M, Reyes, A, Vergani, L, Angeli, P, Gringeri, E, Jacobs, HT, Holt, IJ
JournalCell
Volume111
Issue4
Pagination495-505
Date Published2002 Nov 15
ISSN0092-8674
KeywordsAnimals, DNA Replication, DNA, Mitochondrial, DNA, Single-Stranded, DNA-Binding Proteins, Mitochondria, Liver, Nucleic Acid Hybridization, Rats, Ribonuclease H, Ribonucleotides, RNA, RNA, Mitochondrial, Single-Strand Specific DNA and RNA Endonucleases
Abstract

Recently, we presented evidence for conventional, strand-coupled replication of mammalian mitochondrial DNA. Partially single-stranded replication intermediates detected in the same DNA preparations were assumed to derive from the previously described, strand-asymmetric mode of mitochondrial DNA replication. Here, we show that bona fide replication intermediates from highly purified mitochondria are essentially duplex throughout their length, but contain widespread regions of RNA:DNA hybrid, as a result of the incorporation of ribonucleotides on the light strand which are subsequently converted to DNA. Ribonucleotide-rich regions can be degraded to generate partially single-stranded molecules by RNase H treatment in vitro or during DNA extraction from crude mitochondria. Mammalian mitochondrial DNA replication thus proceeds mainly, or exclusively, by a strand-coupled mechanism.

DOI10.1016/s0092-8674(02)01075-9
Alternate JournalCell
Citation Key10.1016/s0092-8674(02)01075-9
PubMed ID12437923
Grant ListMC_U105663140 / / Medical Research Council / United Kingdom