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Translocation of active mitochondria during hamster preimplantation embryo development studied by confocal laser scanning microscopy
Author(s) -
Barnett Deborah K.,
Kimura Junpei,
Bavister Barry D.
Publication year - 1996
Publication title -
developmental dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.634
H-Index - 141
eISSN - 1097-0177
pISSN - 1058-8388
DOI - 10.1002/(sici)1097-0177(199601)205:1<64::aid-aja6>3.0.co;2-3
Subject(s) - biology , embryo , hamster , confocal laser scanning microscopy , microbiology and biotechnology , chromosomal translocation , confocal , confocal microscopy , laser microscopy , biophysics , genetics , optics , gene , physics
The role of mitochondrial metabolism in the development of preimplantation embryos isunclear. To clarify the importance of mitochondria in early development, the fluorescent probesrhodamine 123 (Rh123: stains active mitochondrial membrane) and nonyl acridine orange (NAO:stains active and inactive mitochondrial membrane) were used with confocal laser scanningmicroscopy to study the distribution of mitochondria in hamster unfertilized follicular andoviductal eggs (11.5 hr and 16 hr post‐hCG, respectively) and preimplantation embryos (1‐cellto blastocyst). Rh123 staining indicated that active mitochondria were homogeneously distributedin unfertilized follicular and oviductal eggs. At 3 hr post egg activation (PEA) by sperm, activemitochondria were still found throughout the cytoplasm of the activated egg although they wereslightly clustered around the pronuclei and were intensely active in the second polar body. Duringthe next 9 hr, the majority of active mitochondria encircled the apposing pronuclei. By this timethe second polar body no longer stained. In 2‐cell, 4‐cell and 8‐cell embryos, there was a strikingconstancy in the pattern of active mitochondria which were clustered around the nuclei anddelineating the cytocortex subjacent to the plasma membrane. In the blastocyst, activemitochondria were most readily detected in the trophectoderm cells in a homogeneousdistribution. Staining mitochondria with NAO showed the same distribution patterns as Rh123,indicating that perinuclear clustering of active mitochondria involves the physical movement ofthese organelles rather than simply changes in their activity. Distribution of actin microfilamentsand microtubules showed similar patterns to mitochondria and may be involved in theirmovement. This migration of mitochondria, beginning during the early stages of fertilization inthe hamster egg and persisting until blastocoel formation, must have some functional correlationwith successful preimplantation development. © 1996 Wiley‐Liss, Inc.