中国生物工程杂志

In animal cloning, it is generally believed that the inactive diploid G0 or G1 stage of the cell cycle is beneficial to initiate cell-cycle coordination and reprogramming following transfer of the donor nucleus. In order to provide more G0+G1 stage cells for dairy cattle cloning, we carried out a flow cytometric analysis of the cell cycle of fibroblasts from the ear of dairy cow at different passage numbers after different periods of serum, after full confluence, after cycloheximide（CHX） treatment. Serum starvation effectively increased the percentage of G0+G1 sage cells after 72h. Significantly higher percentage of cells in G0+G1 was apparent when dairy cattle fibroblast cells cultured in confluence. No significant difference were observed on the 3rd passage cultures exposed to CHX, however, on the 13th passage an increase on proportion of cells was observed after all periods of exposure(p<0.05). This date indicates that high passage cells in vitro are more susceptible to serum starvation, confluence cultured and CHX G0+G1 synchronization.