Nuclear remodelling and the developmental potential of nuclear transferred porcine oocytes under delayed-activated conditions.
It is still unclear whether nuclear envelope breakdown and premature chromosome condensation are essential for the reprogramming of the donor nucleus following somatic nuclear transfer. To address this, we determined the ability of delayed-activated or simultaneously activated porcine oocytes to undergo nuclear remodelling and development following somatic cell nuclear transfer. A small microtubule aster was observed in association with decondensed chromatin following nuclear transfer, suggesting the introduction of a somatic cell centrosome. In the delayed-activated condition, most fibroblast nuclei divided into two chromosome masses and two pronuclear-like structures following transfer into oocytes. In contrast, fibroblast nuclei in the simultaneously activated condition formed a large, swollen, pronuclear-like structure. Microtubule asters were organised in the vicinity of the nucleus regardless of the number of nuclei. More reconstructed oocytes developed to the blastocyst stage in the delayed-activated condition than in the simultaneously activated condition (p < 0.05). Nine piglets were born from two recipient sows following transfer of delayed-activated reconstructed oocytes, while none developed to full term in the simultaneously activated condition. Fingerprint analysis showed that the PCR-RFLP patterns of the nine offspring were identical to that of the donor pig. These results suggest that the activation of recipient oocytes during nuclear transfer probably relates to the nuclear remodelling process, which can affect the ability of embryos created by somatic cell nuclear transfer to develop.
Yin
Xi-Jun
XJ
Division of Applied Life Science, GyeongSang National University, Chinju, GyeongNam, Korea.
Cho
Seong-Keun
SK
Park
Mi-Ryeung
MR
Im
Yeo-Jeoung
YJ
Park
Joung-Ju
JJ
Jong-Sik-Bhak
Kwon
Deug-Nam
DN
Jun
Sun Hong
SH
Kim
Nam-Hyung
NH
Kim
Jin-Hoi
JH
D000818:Animals; D002467:Cell Nucleus / Q000502:physiology*; D002843:Chromatin / Q000502:physiology; D019976:Cloning, Organism; D008870:Microtubules / Q000502:physiology; D053652:Nuclear Transfer Techniques; D009865:Oocytes / Q000502:physiology*; D013552:Swine / Q000196:embryology / Q000502:physiology*
D002843:Chromatin