Sie befinden Sich nicht im Netzwerk der Universität Paderborn. Der Zugriff auf elektronische Ressourcen ist gegebenenfalls nur via VPN oder Shibboleth (DFN-AAI) möglich. mehr Informationen...
The PPR domain of mitochondrial RNA polymerase is an exoribonuclease required for mtDNA replication in Drosophila melanogaster
Ist Teil von
Nature cell biology, 2022-05, Vol.24 (5), p.757
Ort / Verlag
England
Erscheinungsjahr
2022
Link zum Volltext
Quelle
MEDLINE
Beschreibungen/Notizen
Mitochondrial DNA (mtDNA) replication and transcription are of paramount importance to cellular energy metabolism. Mitochondrial RNA polymerase is thought to be the primase for mtDNA replication. However, it is unclear how this enzyme, which normally transcribes long polycistronic RNAs, can produce short RNA oligonucleotides to initiate mtDNA replication. We show that the PPR domain of Drosophila mitochondrial RNA polymerase (PolrMT) has 3'-to-5' exoribonuclease activity, which is indispensable for PolrMT to synthesize short RNA oligonucleotides and prime DNA replication in vitro. An exoribonuclease-deficient mutant, PolrMT
, partially restores mitochondrial transcription but fails to support mtDNA replication when expressed in PolrMT-mutant flies, indicating that the exoribonuclease activity is necessary for mtDNA replication. In addition, overexpression of PolrMT
in adult flies leads to severe neuromuscular defects and a marked increase in mtDNA transcript errors, suggesting that exoribonuclease activity may contribute to the proofreading of mtDNA transcription.