CHD4 Ensures Bovine Early Embryogenesis by Restricting Developmental Gene Expression and Maintaining BRG1 Expression

Area of Science:

• Developmental Biology
• Epigenetics
• Genomics

Background:

• ATP-dependent chromatin remodeling proteins regulate gene expression and chromosome function.
• The role of CHD4 in mammalian embryogenesis is not fully understood, despite its known function in mice trophectoderm formation and implantation.

Purpose of the Study:

• To investigate the species-specific function of CHD4 in early bovine embryogenesis.
• To elucidate the molecular mechanisms by which CHD4 influences bovine embryonic development.

Main Methods:

• CHD4 depletion in bovine embryos.
• Transcriptome analysis (RNA-seq) of 16-cell embryos.
• Assay for Transposase-Accessible Chromatin using sequencing (ATAC-seq).
• Immunofluorescence for histone modifications.

Main Results:

• CHD4 depletion caused developmental arrest at the 16-32-cell stage and failure to form blastocysts.
• Loss of CHD4 led to differential expression of 652 genes, including many developmental genes.
• Altered gene expression correlated with changes in chromatin accessibility and histone modifications (H3K27ac, H3K9me3).
• CHD4 depletion increased trophectoderm marker keratin expression and global chromatin accessibility.
• BRG1 protein levels were significantly reduced in CHD4-depleted embryos.

Conclusions:

• CHD4 is essential for preventing developmental arrest and ensuring proper gene expression during early bovine development.
• CHD4 restricts developmental gene expression and maintains BRG1 levels, facilitating the 16- to 32-cell stage transition.
• These findings reveal a critical, species-specific role for CHD4 in bovine embryogenesis.