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Effect of activation time on the nuclear remodeling and in vitro development of nuclear transfer embryos derived from bovine somatic cells
Author(s) -
Choi JongYeob,
Kim ChoungIk,
Park ChoonKeun,
Yang BooKeun,
Cheong HeeTae
Publication year - 2004
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.20131
Subject(s) - biology , pronucleus , embryo , premature chromosome condensation , chromatin , andrology , somatic cell , in vitro , blastocyst , microbiology and biotechnology , zygote , oocyte activation , oocyte , genetics , embryogenesis , dna , gene , medicine
This study was conducted to investigate the effect of recipient activation time on the chromatin structure and development of bovine nuclear transfer embryos. Serum‐starved skin cells were electrofused to enucleated oocytes, activated 1–5 hr after fusion, and cultured in vitro. Some fused eggs were fixed at each time point after fusion without activation, or 3 or 7 hr after activation. Some nocodazole treated zygotes were fixed to analyze their chromosome constitutions. The proportion of eggs with a morphologically normal premature chromosome condensation (PCC) state increased 1–2 hr after fusion. Whereas eggs with elongated chromosome plate increased as activation time was prolonged to 3 hr, and 5 hr after fusion, 58.1% of eggs showed more than two scattered chromosome sets. The proportion of eggs with a single chromatin mass (40.6–56.7%) significantly increased when eggs were activated within 2.5 hr after fusion ( P < 0.05). Only 23.3% of reconstituted embryos activated 5 hr after fusion formed one pronucleus‐like structure (PN), whereas, 64.5–78.3% of embryos activated 1–2.5 hr after fusion formed one PN. The proportion of embryos with normal chromosome constitutions decreased as activation time was prolonged. Development rates to the blastocyst stage were higher in eggs activated within 2 hr after fusion (17.3–21.7%) compared to those of others (0–8.6%, P < 0.05). The result of the present study suggests that activation time can affect the chromatin structure and in vitro development of bovine nuclear transfer embryos. Mol. Reprod. Dev. 69: 289–295, 2004. © 2004 Wiley‐Liss, Inc.