The effects of delayed activation and MG132 treatment on nuclear remodeling and preimplantation development of embryos cloned by electrofusion are correlated with the age of recipient cytoplasts.
The electrofusion method, used extensively in livestock cloning, cannot be used in mice, because it is believed that the mouse oocytes are more susceptible to detrimental effects of electrical stimulus than oocytes from other species. Reports on whether a delayed activation after electrofusion and a premature chromosome condensation (PCC) is essential for efficient cloning are inconclusive. To address these issues, effects of pulsing on activation and MPF activity of nonenucleated oocytes and effects of delayed activation and MG132 treatment on donor nuclear PCC and preimplantation development of embryos cloned by electrofusion or nuclear injection were compared between different cytoplast ages in mice and goats. The results indicated that the use of oocytes collected early after donor stimulation would make it possible to conduct somatic cell nuclear transfer in mice by electrofusion. Whether a delayed activation is essential was dependent upon the age, or rather, the level, of MPF activity of the cytoplasts at the time of electrofusion, as was the requirement for MG132 treatment. The competence for blastocyst formation of cloned embryos was highly correlated with the level of donor nuclear PCC in recipient cytoplasts. The nuclear injection technique was more adaptable to older cytoplast ages, and hence less dependent on drugs for inhibition of MPF inactivation, compared to electrofusion.
Wu
Yan-Guang
YG
College of Animal Science & Vet Medicine, Shandong Agricultural University, Tai-an City, People's Republic of China.
Zhou
Ping
P
Lan
Guo-Cheng
GC
Wang
Gang
G
Luo
Ming-Jiu
MJ
Tan
Jing-He
JH
D000375:Aging / Q000502:physiology*; D000818:Animals; D001755:Blastocyst / Q000187:drug effects / Q000502:physiology; D002459:Cell Fusion / Q000379:methods; D002467:Cell Nucleus / Q000502:physiology*; D002478:Cells, Cultured; D002869:Chromosome Aberrations / Q000187:drug effects / Q000196:embryology; D019976:Cloning, Organism / Q000379:methods*; D004558:Electric Stimulation; D004622:Embryo, Mammalian / Q000166:cytology / Q000502:physiology*; D047108:Embryonic Development; D005260:Female; D006041:Goats; D007976:Leupeptins / Q000494:pharmacology*; D008297:Male; D000090204:Mesothelin; D051379:Mice; D053652:Nuclear Transfer Techniques; D009865:Oocytes / Q000166:cytology / Q000187:drug effects
D007976:Leupeptins; C000715528:Msln protein, mouse; D000090204:Mesothelin; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde