scholarly journals Role of the mitochondrial DNA replication machinery in mitochondrial DNA mutagenesis, aging and age-related diseases

2017 ◽  
Vol 33 ◽  
pp. 89-104 ◽  
Author(s):  
Karen L. DeBalsi ◽  
Kirsten E. Hoff ◽  
William C. Copeland
Keyword(s):  
Mitochondrial Dna ◽  
Dna Replication ◽  
Replication Machinery ◽  
Age Related ◽  
Mitochondrial Dna Replication ◽  
Dna Mutagenesis

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

2015 ◽  
Vol 112 (30) ◽  
pp. 9334-9339 ◽  
Author(s):  
J. Bradley Holmes ◽  
Gokhan Akman ◽  
Stuart R. Wood ◽  
Kiran Sakhuja ◽  
Susana M. Cerritelli ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Dna Replication ◽  
Strand Break ◽  
Initiation Site ◽  
Major Noncoding Region ◽  
Mitochondrial Dna Replication ◽  
Strand Initiation ◽  
Mitochondrial Dna Polymerase ◽  
Dna Maintenance

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.

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