Maternal SIN3A regulates reprogramming of gene expression during mouse preimplantation development

Area of Science:

• Developmental Biology
• Epigenetics
• Molecular Biology

Background:

• The transition from oocyte to embryo requires genome activation and gene expression reprogramming.
• A transcriptionally repressive chromatin state develops during this transition.
• Histone deacetylases 1 and 2 (HDAC1 and HDAC2) contribute to establishing this repressive state.

Purpose of the Study:

• To investigate the role of the SIN3A complex, containing HDAC1/2, in reprogramming gene expression during genome activation.
• To determine if SIN3A is involved in the maternal control of early embryonic development.

Main Methods:

• Studied the recruitment of Sin3a mRNA during oocyte maturation and early embryonic development.
• Inhibited Sin3a mRNA recruitment to assess its impact on development and gene expression reprogramming.
• Analyzed SIN3A protein levels throughout early embryonic stages.
• Examined the effects of SIN3A overexpression on embryonic development.

Main Results:

• Sin3a mRNA is recruited during oocyte maturation, with SIN3A protein peaking in mid-1-cell embryos and decreasing by the mid-2-cell stage.
• Inhibiting Sin3a mRNA recruitment arrested development beyond the 2-cell stage and impaired gene expression reprogramming fidelity.
• Overexpression of SIN3A did not affect pre- or postimplantation development.

Conclusions:

• SIN3A, recruited via maternal mRNA, plays a critical role in reprogramming gene expression during early embryonic development.
• This mechanism utilizes maternally inherited transcription machinery, including chromatin remodelers like SIN3A, for developmental progression.
• SIN3A is essential for the fidelity of gene expression reprogramming required for development beyond the 2-cell stage.