Fig. 3

Schematic representation of mitochondrial gene editing strategies. mtDNA replication and transcription initiation: TFAM drives mtDNA replication and transcription, while POLRMT and TFB2M help form the initiation complex at the promoter region. Transcription elongation: After the dissociation of TFAM and TFB2M, POLRMT binds to TEFM for transcription elongation, producing longer transcripts. mtDNA mutant correction: mtDNA mutations are targeted and corrected by nuclease and base editors or suppressed during replication by blockers. Transcription maturation: Transcripts undergo maturation via hydrolytic cleavage by RNase P and ELAC2. a mtDNA programmable nucleases: A depiction of programmable nucleases, such as CRISPR-Cas9, designed to target specific sequences in the mitochondrial DNA (mtDNA), enabling precise editing or repair of genetic mutations within the mitochondria. b mtDNA base editors: Schematic showing the use of base editors to induce point mutations in mtDNA without causing double-strand breaks, offering a safer alternative for correcting specific genetic mutations. c mtDNA anti-replication: Illustration of strategies to inhibit mtDNA replication, including the use of specific blockers that prevent the replication of mutant mtDNA, thus controlling the spread of mutations. d mtRNA regulation: Depiction of methods for regulating mitochondrial RNA (mtRNA) expression, including the use of antisense oligonucleotides (ASOs), RNA interference (RNAi), or RNA-targeting nucleases to modulate mitochondrial gene expression. e mtRNA substitution: Illustration of the substitution strategy for defective mitochondrial RNAs (mtRNA), such as mt-mRNA, mt-tRNA, and mt-rRNA, to restore normal mitochondrial function by replacing mutated or defective RNA species with functional ones. ASOs antisense oligonucleotides, ELAC2 elaC ribonuclease Z2, HSD17B10 hydroxysteroid (17-beta) dehydrogenase 10, mtDNA mitochondrial DNA, mtRNA mitochondrial RNA, PIN PilT N-terminus, POLRMT mitochondrial DNA-directed RNA polymerase, PRORP proteinaceous RNase P, PUF Pumilio and FBF, RISC RNA-induced silencing complex, RNase P endonuclease P, RNAi RNA interference, shRNA short hairpin RNA, siRNA small interfering RNA, TEFM transcription elongation factor, TFAM mitochondrial transcription factor A, TFB2M mitochondrial transcription factor B2, TRMT10C tRNA methyltransferase 10C (Generated by the authors with Adobe Illustrator)