title: Mitochondrial distribution and microtubule organization in fertilized and cloned porcine embryos: implications for developmental potential.
abstract: Mitochondrial distribution and microtubule organization were examined in porcine oocytes after parthenogenesis, fertilization and somatic cell nuclear transfer (SCNT). Our results revealed that mitochondria are translocated from the oocyte's cortex to the perinuclear area by microtubules that either constitute the sperm aster in in vitro-fertilized (IVF) oocytes or originate from the donor cell centrosomes in SCNT oocytes. The ability to translocate mitochondria to the perinuclear area was lower in SCNT oocytes than in IVF oocytes. Sperm-induced activation rather than electrical activation of SCNT oocytes as well as the presence of the oocyte spindle enhanced perinuclear mitochondrial association with reconstructed nuclei, while removal of the oocyte spindle prior to sperm penetration decreased mitochondrial association with male pronuclei without having an apparent effect on microtubules. We conclude that factors derived from spermatozoa and oocyte spindles may affect the ability of zygotic microtubules to translocate mitochondria after IVF and SCNT in porcine oocytes. Mitochondrial association with pronuclei was positively related with embryo development after IVF. The reduced mitochondrial association with nuclei in SCNT oocytes may be one of the reasons for the low cloning efficiency which could be corrected by adding yet to be identified, sperm-derived factors that are normally present during physiological fertilization.
authors.affiliation: Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri-Columbia, MO, USA.
authors.forename: Mika
authors.initials: M
authors.lastname: Katayama
authors.forename: Zhisheng
authors.initials: Z
authors.lastname: Zhong
authors.forename: Liangxue
authors.initials: L
authors.lastname: Lai
authors.forename: Peter
authors.initials: P
authors.lastname: Sutovsky
authors.forename: Randall S
authors.initials: RS
authors.lastname: Prather
authors.forename: Heide
authors.initials: H
authors.lastname: Schatten
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D004558:Electric Stimulation; D004622:Embryo, Mammalian / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D005333:Fetus / Q000166:cytology / Q000187:drug effects; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D008297:Male; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism*; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D015739:Nocodazole / Q000494:pharmacology; D053652:Nuclear Transfer Techniques; D009865:Oocytes / Q000166:cytology / Q000187:drug effects; D035845:Research Embryo Creation / Q000379:methods*; D013084:Sperm-Ovum Interactions; D008941:Spindle Apparatus / Q000187:drug effects / Q000378:metabolism; D013552:Swine
chemical_list: D015739:Nocodazole