Abstract
Coactivator-associated arginine methyltransferase 1 (CARM1) is involved in both establishment of first pluripotent lineage and pluripotency maintenance of embryonic stem cells (ESCs) in mice. However, the histone substrates and role of CARM1 in early embryonic development remain largely unknown. Here, we show that CARM1 specifically catalyzes H3R26me2 to promote porcine blastocyst formation. The putative histone substrates of CARM1, including H3R2me2, H3R17me2, and H3R26me2, are present in pig early embryos. The changes of CARM1 mRNA during early embryogenesis parallel that of H3R26me2. Functional studies using a combinational approach of chemical inhibition and RNA interference (RNAi) showed that catalytic activity inhibition of CARM1 protein or knockdown (KD) of CARM1 mRNA did not alter the levels of both H3R2me2 and H3R17me2, but significantly reduced H3R26me2 levels in porcine embryos. Furthermore, CARM1 inhibition or KD did not affect embryo development to the 2-cell, 4-cell, 8-cell, and morula stages, but severely compromised blastocyst development. CARM1 knocked down embryos that developed to the blastocyst stage had fewer total cells, inner cell mass (ICM), and trophectoderm (TE) cells. Mechanistically, single embryo RNA-sequencing analysis revealed that CARM1 KD altered the transcriptome characterized by downregulation of key genes associated with Hippo and PI3K-AKT signaling pathways. Taken together, these results demonstrate that CARM1 specifically catalyzes H3R26me2 in porcine embryos and participates in blastocyst development.
Highlights
The blastocyst formation is an important cellular event during preimplantation embryonic development
To quantify the relative abundance of Coactivator-associated arginine methyltransferase 1 (CARM1) mRNA in early embryos, Quantitative Polymerase Chain Reaction (qPCR) was performed to determine the expression of CARM1 mRNA
The results revealed that CARM1 is expressed in oocytes and embryos, but the expression levels of CARM1 mRNA are significantly higher in embryos at the 4-cell and 8-cell stages compared to oocytes, morulae, and blastocysts (Figure 1A) (P < 0.05)
Summary
The blastocyst formation is an important cellular event during preimplantation embryonic development. The first cell segregation generates pluripotent and differentiating lineages, leading to the formation of ICM and TE in blastocysts (Chazaud and Yamanaka, 2016; White and Plachta, 2020). The first lineage specification is tightly regulated by the restricted. Epigenetic regulation on the chromatin is critical for establishing lineage-specific gene expression during early embryogenesis. Accumulating studies showed that methylation on the DNA (Nakanishi et al, 2012) and histone lysine residues (Gao et al, 2010; Liu et al, 2016), and accessible chromatin landscape (Yang et al, 2020) present asymmetrical distribution between ICM and TE in blastocysts and play essential roles in the lineage specification. Epigenetic regulation of the first lineage specification with histone arginine methylation remains poorly understood
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.