| Zygotic genome activation(ZGA)is the first transcriptional event in the life process,and development arrest of human embryos shows highly correlation with ZGA failure in the clinic.In the process of early embryonic development,embryonic development is first regulated by maternal factors,indicating that maternal factors play an important role in embryonic development.Although a few studies have shown that maternal factor have been linked to mammalian ZGA,it is still challenging to explore more maternal factors associated with ZGA.Based on bioinformatics analysis and embryo experiments,this study identified more maternal factors related to ZGA and their relationship with zygotic genome activation.The results are as follows :1.Trim75 plays a role in the transformation of m ESCs into 2CLCsBased on the published single-cell RNA sequencing data of Dux-mediated transformation of m ESCs into 2c-like,the cell clusters and genes representing 2c-like were screened out by cluster analysis,RNA velocity analysis and pseudo-time construction analysis based on bioinformatics analysis techniques.The Ribo-lite data of mouse preimplantation embryos at different stages were subjected to hierarchical clustering analysis to obtain genes highly expressed only in oocytes,fertilized eggs and early 2-cell embryos,and then they were overlapped with various gene sets to obtain maternal factor Trim75.Analysis at the RNA and translation level revealed that Trim75 was highly expressed in oocytes and early 2-cell stage of mouse preimplantation embryos.Therefore,Trim75 is involved in the transformation of m ESCs into 2CLCs and may affect zygotic genome activation.2.Trim75 positively regulates minor zygotic genome activationOverexpression of Trim75 mRNA was microinjected into fertilized eggs.Compared with normal embryonic development,embryos overexpressing Trim75 could develop from fertilized eggs to blastocysts,and there was no significant difference in embryonic development rate.RNA-seq was performed on normal 2-cell embryos and Trim75 overexpressed 2-cell embryos.It was found that 948 genes were up-regulated in Trim75 overexpressed 2-cells and were highly expressed in fertilized eggs and early 2-cell stages.Further alignment analysis showed that 22.05 % of these up-regulated genes regulated the activation of minor zygotic genome activation.The up-regulated genes after overexpression of Trim75 were significantly enriched in metabolic pathways and protein binding processes through GO and KEGG analysis.Therefore,Trim75 is associated with minor zygotic genome activation and plays a role in metabolic pathways and protein binding.3.Trim75 could establish H3K27 ac by collecting EP300From the above results and existing research results,Trim75 may regulate transcription by recruiting other regulatory factors.PPI analysis showed that Trim75 could interact with EP300,an important acetyltransferase in early embryonic development.CUT & Tag data analysis showed that Trim75-dependent genes showed stronger H3K27 ac signal than Trim75-independent genes.In summary,this study analyzed and screened a maternal factor Trim75,Trim75 establishes H3K27 ac by recruiting EP300,promotes secondary ZGA activation,and thus contributes to embryonic development.Trim75 may be clinically used as a biomarker of oocyte quality and provide data support for exploring early embryonic development. |
