Effects of synchronization of donor cell cycle on embryonic development and DNA synthesis in porcine nuclear transfer embryos.

摘要

The relationship between donor cell cycle and the developmental ability of somatic cell nuclear transfer (SCNT) embryos has not been fully elucidated. Donor cells that are usually prepared by serum starvation or confluent-cell culture for SCNT represent a heterogeneous population that includes mainly GO phase cells, other cells in different phases of the cell cycle and apoptotic cells. In this study, the developmental ability of porcine SCNT embryos reconstructed from G0 phase cells (G0-SCNT embryos) and strictly synchronized-G1 phase cells (G1-SCNT embryos) was compared. The developmental rates and timing of first DNA synthesis were examined. The G0 phase cells were synchronized by confluent culture, and the G1 phase cells were prepared from actively dividing M phase cells. The G1-SCNT embryos showed a significantly higher (P<0.05) developmental rate to the blastocyst stage per cleaved embryo (59%) than the G0-SCNT embryos (43%). Moreover, initiation of first DNA synthesis and cleavage occurred significantly earlier in the G1-SCNT embryos than in the G0-SCNT embryos. Delay of initiation of first DNA synthesis in the SCNT embryos by aphidicolin resulted to decreased developmental rates to the blastocyst stage without any effect on cleavage rates. The data demonstrated that synchronized-G1 phase cells could be used as donor cells for SCNT embryos and that earlier initiation of first DNA synthesis might be important for subsequent development of SCNT embryos. The SCNT system using G1-synchronized cells, in terms of their highly uniform and viable cell states, could be useful for studying the reprogramming processes and embryonic development of SCNT embryos..