title: The study of mitochondrial gene modifications in human placenta.
abstract: A quantitative study on the effects of placental senescence on mitochondrial DNA (mtDNA) was carried out by measuring mitochondrial gene mutation, levels of mRNA for the cytochrome c oxidase subunit I (COI) and of mtDNA in normal placental tissues at different stages. Deleted mtDNA, the expression of COI in mitochondria and the amounts of mtDNA per cell were examined by the polymerase chain reaction, northern blot analysis and southern blot analysis, respectively. No accumulation of mutant mtDNA with a 4977 base pair (bp) deletion was detected in the normal placenta during pregnancy. There appeared to be a gradual increase of COI mRNA as pregnancy progressed, while the ratio of mtDNA to total DNA in human placenta tended to decrease with gestation. These results indicate that placental ageing is not associated with the accumulation of mtDNA mutation with the 4977 bp deletion or markedly reduced expression of the mitochondrial genome.
mesh_terms: D001483:Base Sequence; D004272:DNA, Mitochondrial / Q000235:genetics*; D003576:Electron Transport Complex IV / Q000235:genetics*; D005260:Female; D017353:Gene Deletion; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D006801:Humans; D008969:Molecular Sequence Data; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D012016:Reference Values
chemical_list: D004272:DNA, Mitochondrial; D003576:Electron Transport Complex IV