Donor cells at the G1 phase enhance homogeneous gene expression among blastomeres in bovine somatic cell nuclear transfer embryos.
The success rate of bovine somatic cell nuclear transfer (SCNT) embryos to full term has been reported to be higher with G1 cells than with G0 cells. To better understand the reason for this, we analyzed the kinetics of luminescence activity in bovine SCNT embryos from G0 and G1 cells carrying a luciferase gene under the control of the β-actin promoter during early embryonic development. At 60-h postfusion, when bovine embryonic gene activation (EGA) begins, the luminescence activity was higher in G1-SCNT embryos than G0-SCNT embryos. Moreover, half of the G1-SCNT embryos exhibited homogeneous luminescence among the blastomeres, whereas more than half of the G0-SCNT embryos exhibited mosaic luminescence. To characterize the differential luminescence pattern in SCNT embryos, the expressions of several endogenous genes and the level of DNA methylation were determined in all blastomeres of SCNT embryos with or without luminescence. The expressions of several development-related genes (H2AFZ, GJA1, and BAX) and level of DNA methylation of the SCNT embryos with luminescence were the same as those of normal embryos produced by in vitro fertilization. A higher success rate in G1-SCNT embryos is thought to contribute to homogeneous expression among all blastomeres at EGA.
Department of Genetic Engineering, Kinki University, Kinokawa, Wakayama, Japan.
Daisaku
D
Iwamoto
Aya
A
Kasamatsu
Atsushi
A
Ideta
Manami
M
Urakawa
Kazuya
K
Matsumoto
Yoshihiko
Y
Hosoi
Akira
A
Iritani
Yoshito
Y
Aoyagi
Kazuhiro
K
Saeki
D000199:Actins / Q000378:metabolism; D000818:Animals; D001757:Blastomeres / Q000166:cytology / Q000378:metabolism*; D002417:Cattle; D018031:Connexin 43 / Q000378:metabolism; D004622:Embryo, Mammalian / Q000166:cytology / Q000378:metabolism; D047108:Embryonic Development / Q000502:physiology*; D005260:Female; D005307:Fertilization in Vitro; D005347:Fibroblasts / Q000166:cytology* / Q000502:physiology; D016193:G1 Phase / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D066298:In Vitro Techniques; D008156:Luciferases / Q000378:metabolism; D008297:Male; D023421:Models, Animal; D053652:Nuclear Transfer Techniques; D016192:Resting Phase, Cell Cycle / Q000502:physiology; D051028:bcl-2-Associated X Protein / Q000378:metabolism
D000199:Actins; D018031:Connexin 43; D051028:bcl-2-Associated X Protein; D008156:Luciferases