title: Development of goat embryos reconstituted with somatic cells: the effect of cell-cycle coordination between transferred nucleus and recipient oocytes.
abstract: The developmental ability and the nucleus and microtubule dynamics of nuclear transplanted goat embryos derived from in vitro matured oocytes were studied while controlling cell-cycle coordination of donor embryonic nuclei and recipient cytoplasts. Three groups of transfers were studied: G0/G1 (after the fibroblast cells grew to 100% confluence) and G2/M (nocodazole treated) phase fibroblasts transferred to MII cytoplasts (G0/G1-->MII and G2/M-->MII group, respectively), and G0/G1 phase fibroblasts transferred to preactivated cytoplasts, mostly at S-phase, (G0/G1-->Pre group) by electrical fusion. The results showed that fusion and developmental ability did not differ between G0/G1-->MII and G0/G1-->Pre groups. However the developmental rate of embryos in the G0/G1-->MII group was significantly higher than that of the G2/M-->MII group. Most fibroblast nuclei (G0/G1 and G2/M) transferred into MII oocytes underwent premature chromosome condensation (PCC). Normal spindle were only detected in the G0/G1-->MII group. In contract, fibroblast nuclei in pre-activated oocytes rarely underwent PCC, but formed a swollen nuclear structure. The data suggest that in vitro matured goat oocytes can support the development of somatic fibroblasts after nuclear transfer, G0/G1 -->MII and G0/G1-->S nuclear transfer might be effective ways for improving the developmental competence of the reconstituted embryos, and that G2/M-->MII nuclear transfer by electrical fusion (even in Ca2+-free fusion medium) induces abnormal chromosome ploidy.
authors.affiliation: State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.
authors.forename: Li-Sheng
authors.initials: LS
authors.lastname: Zhang
authors.forename: Man-Xi
authors.initials: MX
authors.lastname: Jiang
authors.forename: Zi-Li
authors.initials: ZL
authors.lastname: Lei
authors.forename: Rui-Chang
authors.initials: RC
authors.lastname: Li
authors.forename: Dan
authors.initials: D
authors.lastname: Sang
authors.forename: Qing-Yuan
authors.initials: QY
authors.lastname: Sun
authors.forename: Da-Yuan
authors.initials: DY
authors.lastname: Chen
mesh_terms: D000818:Animals; D018929:Cell Culture Techniques / Q000379:methods*; D002453:Cell Cycle; D002467:Cell Nucleus / Q000378:metabolism*; D046149:Embryo Culture Techniques; D004622:Embryo, Mammalian / Q000166:cytology*; D005260:Female; D005347:Fibroblasts / Q000378:metabolism; D006041:Goats; D007150:Immunohistochemistry; D018613:Microscopy, Confocal; D008870:Microtubules / Q000378:metabolism; D009865:Oocytes / Q000166:cytology*; D008941:Spindle Apparatus; D013997:Time Factors