Mitochondrial biogenesis in early mouse embryos: expression of the mRNAs for subunits IV, Vb, and VIIc of cytochrome c oxidase and subunit 9 (P1) of H(+)-ATP synthase

Mol Reprod Dev. 1995 Jan;40(1):29-35. doi: 10.1002/mrd.1080400105.


The mouse egg contains about 90,000 mitochondria which undergo a buildup of mitochondrial cristae and increase in respiratory activity during cleavage. The mitochondrial DNA does not replicate during preimplantation development but is transcribed actively from the two-cell stage onward (Pikó and Taylor, 1987: Dev Biol 123:364-374). To gain further insight into mitochondrial biogenesis, we have now determined the steady state amounts of the mRNAs for the cytochrome c oxidase (COX) subunits IV, Vb and VIIc and the H(+)-ATPase subunit 9 (P1) (all encoded by nuclear genes) in slot hybridization experiments of total RNA from oocytes and early embryos. All four mRNAs showed a similar developmental pattern of prevalence, characterized by a steady decline in mRNA copy numbers from the late growth-phase oocyte through the two-cell embryo, and an about 30-fold rise during cleavage through the blastocyst stage. However, the ATPase subunit 9 (P1) mRNA was about three times more prevalent in cleavage-stage embryos than the COX mRNAs. A similar pattern was obtained previously for the mitochondrial-encoded COX I and II mRNAs, but the latter accumulate at a 30-50-fold excess over the nuclear-encoded COX subunit mRNAs during the cleavage stages. The results suggest a coordinated activation and transcription of the mitochondrial and nuclear genes for the components of the respiratory apparatus beginning with the two-cell stage. It is estimated that new respiratory chains are produced at a rate of 50-100 chains hr-1/mitochondrion in the early blastocyst, accounting for 3.5-7% of the total protein synthetic activity at this stage.(ABSTRACT TRUNCATED AT 250 WORDS)

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Blastocyst / metabolism
  • DNA, Complementary / genetics
  • Electron Transport Complex IV / chemistry
  • Electron Transport Complex IV / genetics*
  • Embryo, Mammalian / metabolism*
  • Embryonic and Fetal Development / genetics
  • Female
  • Gene Expression Regulation, Developmental
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred DBA
  • Mitochondria / metabolism*
  • Oocytes / metabolism
  • Pregnancy
  • Protein Conformation
  • Proton-Translocating ATPases / chemistry
  • Proton-Translocating ATPases / genetics*
  • RNA / genetics
  • RNA / metabolism
  • RNA Probes
  • RNA, Messenger / genetics*
  • RNA, Messenger / metabolism
  • RNA, Mitochondrial


  • DNA, Complementary
  • RNA Probes
  • RNA, Messenger
  • RNA, Mitochondrial
  • RNA
  • Electron Transport Complex IV
  • Proton-Translocating ATPases