title: Transcriptional quiescence of paternal mtDNA in cyprinid fish embryos.
abstract: Mitochondrial homoplasmy signifies the existence of identical copies of mitochondrial DNA (mtDNA) and is essential for normal development, as heteroplasmy causes abnormal development and diseases in human. Homoplasmy in many organisms is ensured by maternal mtDNA inheritance through either absence of paternal mtDNA delivery or early elimination of paternal mtDNA. However, whether paternal mtDNA is transcribed has remained unknown. Here we report that paternal mtDNA shows late elimination and transcriptional quiescence in cyprinid fishes. Paternal mtDNA was present in zygotes but absent in larvae and adult organs of goldfish and blunt-snout bream, demonstrating paternal mtDNA delivery and elimination for maternal mtDNA inheritance. Surprisingly, paternal mtDNA remained detectable up to the heartbeat stage, suggesting its late elimination leading to embryonic heteroplasmy up to advanced embryogenesis. Most importantly, we never detected the cytb RNA of paternal mtDNA at all stages when paternal mtDNA was easily detectable, which reveals that paternal mtDNA is transcriptionally quiescent and thus excludes its effect on the development of heteroplasmic embryos. Therefore, paternal mtDNA in cyprinids shows late elimination and transcriptional quiescence. Clearly, transcriptional quiescence of paternal mtDNA represents a new mechanism for maternal mtDNA inheritance and provides implications for treating mitochondrion-associated diseases by mitochondrial transfer or replacement.
authors.affiliation: State Ministry of Education Key Laboratory of Protein Chemistry and Developmental Biology, College of Life Sciences, Hunan Normal University, Changsha 410081, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Wen
authors.affiliation: State Ministry of Education Key Laboratory of Protein Chemistry and Developmental Biology, College of Life Sciences, Hunan Normal University, Changsha 410081, China.
authors.forename: Liangyue
authors.initials: L
authors.lastname: Peng
authors.affiliation: State Ministry of Education Key Laboratory of Protein Chemistry and Developmental Biology, College of Life Sciences, Hunan Normal University, Changsha 410081, China.
authors.forename: Xinjiang
authors.initials: X
authors.lastname: Hu
authors.affiliation: State Ministry of Education Key Laboratory of Protein Chemistry and Developmental Biology, College of Life Sciences, Hunan Normal University, Changsha 410081, China.
authors.forename: Yuling
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: State Ministry of Education Key Laboratory of Protein Chemistry and Developmental Biology, College of Life Sciences, Hunan Normal University, Changsha 410081, China.
authors.forename: Shaojun
authors.initials: S
authors.lastname: Liu
authors.affiliation: Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore.
authors.forename: Yunhan
authors.initials: Y
authors.lastname: Hong
mesh_terms: D000818:Animals; D003530:Cyprinidae / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000235:genetics*; D047108:Embryonic Development / Q000235:genetics*; D005260:Female; D053263:Gene Regulatory Networks / Q000235:genetics*; D008297:Male; D008928:Mitochondria / Q000235:genetics; D015053:Zygote / Q000502:physiology
chemical_list: D004272:DNA, Mitochondrial