TY - JOUR
T1 - Adult mice cloned from migrating primordial germ cells
AU - Yamazaki, Yukiko
AU - Low, Eleanor W.
AU - Marikawa, Yusuke
AU - Iwahashi, Kazuhiro
AU - Bartolomei, Marisa S.
AU - McCarrey, John R.
AU - Yanagimachi, Ryuzo
PY - 2005/8/9
Y1 - 2005/8/9
N2 - We previously reported that the genomes of gonadal germ cells at 11.5-19.5 days postcoitum (dpc) are incompetent to support full-term development of cloned mouse embryos. In this study, we performed nuclear transfer using primordial germ cells (PGCs) from earlier stages at 8.5-10.5 dpc. When PGC nuclei at 8.5, 9.5, and 10.5 dpc were transferred into enucleated oocytes, seven cloned embryos developed into full-term offspring. Of these, five, all derived from 8.5- or 9.5-dpc PGCs, developed into healthy adults with normal fertility. Of the remaining two offspring derived from 10.5-dpc PGCs, one died shortly after birth, and the other showed slight growth retardation but subsequently developed into a fertile adult. We examined allele-specific methylation at the imprinted H19 and Snrpn loci in 9.5- to 11.5-dpc PGCs. Although the beginning of methylation erasure was evident on the H19 paternal allele at 9.5 dpc, most PGCs did not demonstrate significant erasure of paternal allele-specific methylation until 10.5 dpc. Maternal allele-specific methylation was largely erased from Snrpn by 10.5 dpc. By 11.5 dpc, the majority of PGCs showed nearly complete or complete erasure of allele-specific methylation in both H19 and Snrpn. These results demonstrate that at least some genomic imprints remain largely intact in 8.5- to 9.5-dpc PGCs and then undergo erasure at ≈10.5 dpc as the PGCs enter the genital ridges. Thus, migrating PGCs at 8.5-9.5 dpc can be successfully used as donors for nuclear transfer, whereas gonadal PGCs at 11.5 dpc and later are incompetent to support full-term development.
AB - We previously reported that the genomes of gonadal germ cells at 11.5-19.5 days postcoitum (dpc) are incompetent to support full-term development of cloned mouse embryos. In this study, we performed nuclear transfer using primordial germ cells (PGCs) from earlier stages at 8.5-10.5 dpc. When PGC nuclei at 8.5, 9.5, and 10.5 dpc were transferred into enucleated oocytes, seven cloned embryos developed into full-term offspring. Of these, five, all derived from 8.5- or 9.5-dpc PGCs, developed into healthy adults with normal fertility. Of the remaining two offspring derived from 10.5-dpc PGCs, one died shortly after birth, and the other showed slight growth retardation but subsequently developed into a fertile adult. We examined allele-specific methylation at the imprinted H19 and Snrpn loci in 9.5- to 11.5-dpc PGCs. Although the beginning of methylation erasure was evident on the H19 paternal allele at 9.5 dpc, most PGCs did not demonstrate significant erasure of paternal allele-specific methylation until 10.5 dpc. Maternal allele-specific methylation was largely erased from Snrpn by 10.5 dpc. By 11.5 dpc, the majority of PGCs showed nearly complete or complete erasure of allele-specific methylation in both H19 and Snrpn. These results demonstrate that at least some genomic imprints remain largely intact in 8.5- to 9.5-dpc PGCs and then undergo erasure at ≈10.5 dpc as the PGCs enter the genital ridges. Thus, migrating PGCs at 8.5-9.5 dpc can be successfully used as donors for nuclear transfer, whereas gonadal PGCs at 11.5 dpc and later are incompetent to support full-term development.
KW - DNA methylation imprinted genes
KW - Developmental totipotency
KW - Nuclear transfer
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U2 - 10.1073/pnas.0504943102
DO - 10.1073/pnas.0504943102
M3 - Article
C2 - 16055553
AN - SCOPUS:23844433941
SN - 0027-8424
VL - 102
SP - 11361
EP - 11366
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 32
ER -