Structural rearrangements in the mitochondrial genome of Drosophila melanogaster induced by elevated levels of the replicative DNA helicase

Authors

Grzegorz L. Ciesielski, Department of Biochemistry and Molecular Biology and Center for Mitochondrial Science and Medicine, Michigan State University, East Lansing, MI, USA.
Cristina A. Nadalutti, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
Marcos T. Oliveira, Department of Biochemistry and Molecular Biology and Center for Mitochondrial Science and Medicine, Michigan State University, East Lansing, MI, USA.
Howard T. Jacobs, Institute of Biosciences and Medical Technology, University of Tampere, FI-33014 Tampere, Finland.
Jack D. Griffith, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
Laurie S. Kaguni, Department of Biochemistry and Molecular Biology and Center for Mitochondrial Science and Medicine, Michigan State University, East Lansing, MI, USA.

Document Type

Article

Publication Date

4-6-2018

Subject Area

Animals; Cell Line; DNA Helicases (genetics, metabolism); DNA Replication (genetics); DNA, Mitochondrial (genetics, metabolism); Drosophila Proteins (genetics, metabolism); Drosophila melanogaster (cytology, genetics, metabolism); Gene Dosage; Genome, Mitochondrial (genetics); Mitochondria (genetics, metabolism); Mitochondrial Proteins (genetics, metabolism)

Abstract

Pathological conditions impairing functions of mitochondria often lead to compensatory upregulation of the mitochondrial DNA (mtDNA) replisome machinery, and the replicative DNA helicase appears to be a key factor in regulating mtDNA copy number. Moreover, mtDNA helicase mutations have been associated with structural rearrangements of the mitochondrial genome. To evaluate the effects of elevated levels of the mtDNA helicase on the integrity and replication of the mitochondrial genome, we overexpressed the helicase in Drosophila melanogaster Schneider cells and analyzed the mtDNA by two-dimensional neutral agarose gel electrophoresis and electron microscopy. We found that elevation of mtDNA helicase levels increases the quantity of replication intermediates and alleviates pausing at the replication slow zones. Though we did not observe a concomitant alteration in mtDNA copy number, we observed deletions specific to the segment of repeated elements in the immediate vicinity of the origin of replication, and an accumulation of species characteristic of replication fork stalling. We also found elevated levels of RNA that are retained in the replication intermediates. Together, our results suggest that upregulation of mtDNA helicase promotes the process of mtDNA replication but also results in genome destabilization.

Publication Title

Nucleic acids research

Volume

46

Issue

6

First Page

3034

Last Page

3046

Digital Object Identifier (DOI)

10.1093/nar/gky094

PubMed ID

29432582

E-ISSN

1362-4962

Language

eng

Citation Information

Ciesielski, Grzegorz L.; Nadalutti, Cristina A.; Oliveira, Marcos T.; Jacobs, Howard T.; Griffith, Jack D.; and Kaguni, Laurie S., "Structural rearrangements in the mitochondrial genome of Drosophila melanogaster induced by elevated levels of the replicative DNA helicase" (2018). UNF Faculty Research and Scholarship. 3286.
https://digitalcommons.unf.edu/unf_faculty_publications/3286