Birth of mice produced by germ cell nuclear transfer.
That mammals can be cloned by nuclear transfer indicates that it is possible to reprogram the somatic cell genome to support full development. However, the developmental plasticity of germ cells is difficult to assess because genomic imprinting, which is essential for normal fetal development, is being reset at this stage. The anomalous influence of imprinting is corroborated by the poor development of mouse clones produced from primordial germ cells (PGCs) during imprinting erasure at embryonic day 11.5 or later. However, this can also be interpreted to mean that, unlike somatic cells, the genome of differentiated germ cells cannot be fully reprogrammed. We used younger PGCs (day 10.5) and eventually obtained four full-term fetuses. DNA methylation analyses showed that only embryos exhibiting normal imprinting developed to term. Thus, germ cell differentiation is not an insurmountable barrier to cloning, and imprinting status is more important than the origin of the nucleus donor cell per se as a determinant of developmental plasticity following nuclear transfer.
Miki
Hiromi
H
RIKEN Bioresource Center, Tsukuba, Ibaraki, Japan.
Inoue
Kimiko
K
Kohda
Takashi
T
Honda
Arata
A
Ogonuki
Narumi
N
Yuzuriha
Misako
M
Mise
Nathan
N
Matsui
Yasuhisa
Y
Baba
Tadashi
T
Abe
Kuniya
K
Ishino
Fumitoshi
F
Ogura
Atsuo
A
D000818:Animals; D000831:Animals, Newborn; D002454:Cell Differentiation; D019976:Cloning, Organism / Q000379:methods*; D019175:DNA Methylation; D005260:Female; D018392:Genomic Imprinting; D005854:Germ Cells / Q000166:cytology; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D053652:Nuclear Transfer Techniques; D011247:Pregnancy