Mediator MED23 controls oligodendrogenesis and myelination by modulating Sp1/P300-directed gene programs

Area of Science:

• Neuroscience
• Molecular Biology
• Genetics

Background:

• Myelination is crucial for neurological function.
• Mediator Med23 mutations are linked to intellectual disability and white matter defects.
• The role of Mediator in myelination is not fully understood.

Purpose of the Study:

• To investigate the function of Mediator Med23 in myelination.
• To elucidate the molecular mechanisms underlying Med23-associated hypomyelination.
• To establish a mouse model for studying Med23-related neurological disorders.

Main Methods:

• Generated a mouse model with Med23^Q649R mutation.
• Created oligodendrocyte-specific Med23 knockout mice.
• Utilized in vitro oligodendrocyte differentiation assays.
• Performed gene profiling and reporter assays.
• Conducted integrative analysis of gene regulation.

Main Results:

• Med23^Q649R mice exhibit white matter thinning and cognitive decline.
• Med23 deficiency in oligodendrocytes impairs CNS myelination and remyelination.
• Oligodendrocyte progenitor cells with Med23 mutations or knockout show differentiation deficits.
• Med23 regulates Sp1-driven gene programs in oligodendrocyte differentiation and cholesterol metabolism.
• Med23 modulates P300 binding to Sp1 targets, affecting H3K27 acetylation and enhancer activation.

Conclusions:

• Mediator Med23 plays a critical role in oligodendrocyte fate determination.
• Med23 is essential for central nervous system myelination and remyelination.
• Mechanistic insights into Med23 mutations causing myelination disorders are provided.