biostudies-literatureMeng FMinistry of Science and Technology of ChinaNational Natural Science Foundation of ChinaNational Key Research and Development Program9453-9469https://www.ebi.ac.uk/biostudies/studies/S-EPMC9458427biostudies-literatureUnknown50(16)In this report, we investigated the molecular mechanism underlying a deafness-associated m.5783C > T mutation that affects the canonical C50-G63 base-pairing of TΨC stem of tRNACys and immediately adjacent to 5' end of light-strand origin of mitochondrial DNA (mtDNA) replication (OriL). Two dimensional agarose gel electrophoresis revealed marked decreases in the replication intermediates including ascending arm of Y-fork arcs spanning OriL in the mutant cybrids bearing m.5783C > T mutation. mtDNA replication alterations were further evidenced by decreased levels of PolγA, Twinkle and SSBP1, newly synthesized mtDNA and mtDNA contents in the mutant cybrids. The m.5783C > T mutation altered tRNACys structure and function, including decreased melting temperature, conformational changes, instabNucleic acids researchA deafness-associated mitochondrial DNA mutation caused pleiotropic effects on DNA replication and tRNA metabolism.PMC945842781700922820300282018YFC10048022021YFC270090282071063Meng FWang MZheng JXiao YLing FFu YGuan MXJi YWang JJia ZfalseA deafness-associated mitochondrial DNA mutation caused pleiotropic effects on DNA replication and tRNA metabolism.In this report, we investigated the molecular mechanism underlying a deafness-associated m.5783C > T mutation that affects the canonical C50-G63 base-pairing of TΨC stem of tRNACys and immediately adjacent to 5' end of light-strand origin of mitochondrial DNA (mtDNA) replication (OriL). Two dimensional agarose gel electrophoresis revealed marked decreases in the replication intermediates including ascending arm of Y-fork arcs spanning OriL in the mutant cybrids bearing m.5783C > T mutation. mtDNA replication alterations were further evidenced by decreased levels of PolγA, Twinkle and SSBP1, newly synthesized mtDNA and mtDNA contents in the mutant cybrids. The m.5783C > T mutation altered tRNACys structure and function, including decreased melting temperature, conformational changes, instab2022-01-01T00:00:00Z2022 Sep2025-04-20T00:41:17.134Z2025-04-20T00:41:17.134ZS-EPMC94584273603976310.1093/nar/gkac720