Human mitochondrial degradosome prevents harmful mitochondrial R loops and mitochondrial genome instability

R loops are nucleic acid structures comprising an DNA–RNA hybrid and a displaced single-stranded DNA. These structures may occur transiently during transcription, playing essential biological functions. However, persistent R loops may become pathological as they are important drivers of genome insta...

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Detalhes bibliográficos
Autores: Silva, Sonia, Camino, Lola P., Aguilera, Andrés
Formato: artículo
Estado:Versión publicada
Fecha de publicación:2018
País:España
Recursos:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/180546
Acesso em linha:http://hdl.handle.net/10261/180546
Access Level:acceso abierto
Palavra-chave:Genome instability
Mitochondrial degradosome
R loops
RNA metabolism
Transcription–replication
Conflicts
Descrição
Resumo:R loops are nucleic acid structures comprising an DNA–RNA hybrid and a displaced single-stranded DNA. These structures may occur transiently during transcription, playing essential biological functions. However, persistent R loops may become pathological as they are important drivers of genome instability and have been associated with human diseases. The mitochondrial degradosome is a functionally conserved complex from bacteria to human mitochondria. It is composed of the ATP-dependent RNA and DNA helicase SUV3 and the PNPase ribonuclease, playing a central role in mitochondrial RNA surveillance and degradation. Here we describe a new role for the mitochondrial degradosome in preventing the accumulation of pathological R loops in the mitochondrial DNA, in addition to preventing dsRNA accumulation. Our data indicate that, similar to the molecular mechanisms acting in the nucleus, RNA surveillance mechanisms in the mitochondria are crucial to maintain its genome integrity by counteracting pathological R-loop accumulation.