Effects of overexpression of histone H3K9me3 demethylase on development of porcine cloned embryos.

ABSTRACT

The abnormal modification of histone is an important factor restricting development of porcine cloned embryos. Overexpression of histone H3K9me3 demethylase KDM4 family can effectively improve the developmental efficiency of cloned embryos. In order to explore the effects of overexpression of H3K9me3 demethylase on the development of porcine cloned embryos, KDM4A mRNA and KDM4D mRNA were injected respectively into porcine cloned embryos at the 1-cell stage and 2-cell stage to detect the blastocyst rate; 2-cell stage cloned embryos injected with KDM4A mRNA and embryo injection water (the control group) at the 1-cell stage were collected to detect the expression level of H3K9me3, and 4-cell stage cloned embryos were collected for single cell transcriptome sequencing, then the sequencing data was analyzed with KEGG and GO. The results showed that the blastocyst rate of porcine cloned embryos injected with KDM4A mRNA at 1-cell stage was significantly higher than that of the control group (25.32 ± 0.74% vs 14.78 ± 0.87%), while cloned embryos injected with KDM4D mRNA had a similar blastocyst rate with cloned embryos in control group (16.27 ± 0.77% vs 14.78 ± 0.87%). Porcine cloned embryos injected with KDM4A mRNA and KDM4D mRNA at 2-cell stage had a similar blastocyst rate with cloned embryos in control group (32.18 ± 1.67%, 30.04 ± 0.91% vs 31.22 ± 1.40%). The expression level of H3K9me3 in cloned embryos injected with KDM4A mRNA at 1-cell stage was lower than that in control group. There were 133 differentially expressed genes detected by transcriptome sequencing, including 52 up-regulated genes and 81 down-regulated genes. Pathways enriched by GO analyses were mainly related to protein localization. Pathways enriched by KEGG analyses were related to cellular senescence and acute myeloid leukemia. These results suggest that overexpression of histone H3K9me3 demethylase KDM4A can significantly improve the developmental efficiency of porcine cloned embryos.