PARENT SESSION
SLIDE SESSION 7: REPRODUCTIVE TECHNOLOGIES
Chairs: Nicola Dean, Jay Baltz, Jamie Cowell (Trainee)
Univ Ottawa-Lamoureaux 122
2:30 PM-4:30 PM

CLONING MICE USING NEURONAL CELLS FROM THR EMBRYONIC CEREBRAL CORTEX.

Yamazaki, Yukiko¹, Makino, Hatsune ^2,3, Hamada, Shun ^2,3, Hamaguchi-Hamada, Kayoko^2,3, Kawase, Eihachiro⁴, Ogawa, Masaharu⁵, Yagi, Takeshi^2,3, Yanagimachi, Ryuzo¹, ^{1 2 3 4 5}

ABSTRACT- Nuclear totipotency of developing neuronal cells was examined by transferring the nuclei of embryonic cerebral cortex cells into enucleated mouse oocytes. Neuronal cells were collected from B6D2F1 fetuses at 15.5-17.5 dpc. The cerebral cortex was dissected away from the telencephalic region. First, the cells collected from the entire cortex were used as nuclear donor, with the result that high proportions of the oocytes were activated (96%) and 13% of reconstructed oocytes developed into fetuses by 10.5 day of pregnancy. To examine possible alteration of the nucleus totipotency during differentiation of neurons, cerebral cortex was separated into two fragments, the ventricular side fragment (V-frag) and the pial side fragment (P-frag). The V-frag contained post-meitotic, premature neuronal cells, whereas P-frag contains differentiated neurons. The cells of V-frag and P-frag were used as donor cells for cloning. The majority of the oocytes were activated in both donor cells, and 38 and 27% developed into morulae/blastocysts. These embryos were transferred to surrogate mothers and examined at 10 dpc stage. Thirteen and 6% of the reconstructed oocytes from V-frag and P-frag developed into fetuses, respectively. Furthermore, 5 live pups were obtained from 117 oocytes reconstructed with neuronal nuclei from V-frag(4.3%). All pups developed into healthy fertile adults, indicating that premature neurons have totipotency. We are now trying to determine whether neuronal cells in P-frag region have totipotency.

KEY WORDS: cloning, neuronal cells, differentiation, totipotency