To investigate the possible mechanisms of the abnormal expression patterns of many genes in the embryos in vitro, the expression
of histone acetyltransferase GCN5 and histone deacetylase 1 (HDAC1) were detected in mouse preimplantation embryos. For the in
vitro group, the pronucleus embryos were obtained from superovulated mice, and cultured in vitro to get the two-cell, four-cell, eightcell,
morula and blastocyst stages embryos. For the in vivo group, embryos at different stages were obtained from pregnant mice directly.
Reverse transcription polymerase chain reaction (RT-PCR) and immunocytochemistry were used to detect the mRNA and protein expression
levels of GCN5 and HDAC1. Compared with the embryos in vivo, the expression levels of Gcn5 in the embryos in vitro significantly
increased except those in four-cell embryos. The expression of Gcn5 in eight-cell embryos in vivo and in four-cell and eight-cell embryos
in vitro was higher than those at other stages within the same group. Compared with the expressions of Hdac1 in embryo in vivo, only
those at two-cell embryo in vitro showed decreased level. The expression of Hdac1 enhanced after two-cell embryo stage in vitro, but no
difference showed in vivo. The protein expression of GCN5and HDAC1 in the embryo in vitro at every stage showed a lower level with
the control of those in the embryos in vivo. Our studies indicated that in vitro culture could induce the expressed alteration of GCN5 and
HDAC1, which might be related to the expression patterns of many other epigenetically regulated genes.