Increased mitochondrial transcription initiation does not promote oxidative phosphorylation
L'augmentation de l'initiation de la transcription mitochondriale ne favorise pas la phosphorylation oxydative
Résumé
Increasing POLRMT did not result in any pathological phenotype but instead positively affected exercise capacity under stress conditions. POLRMT overexpression increased in organello transcription initiation, resulting in higher steady-state levels of the promoter-proximal L-strand transcript 7S RNA and higher mtDNA levels. Surprisingly, the abundance of mature mitochondrial RNAs was not affected by the elevated POLRMT levels. Furthermore, ubiquitous simultaneous overexpression of POLRMT and LRPPRC, which stabilizes mitochondrial messenger RNAs, did not increase steady-state levels of mitochondrial transcripts in the mouse. Our data show that POLRMT levels regulate transcription initiation, but additional regulatory steps downstream of transcription initiation and transcript stability limit OXPHOS biogenesis.
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