Targeting G-quadruplex DNA as cognitive function therapy for ATR-X syndrome

Area of Science:

• Genetics
• Neuroscience
• Molecular Biology

Background:

• Alpha-thalassemia X-linked intellectual disability (ATR-X) syndrome results from mutations in the ATRX gene, impacting chromatin remodeling.
• ATRX protein preferentially binds to G-rich sequences capable of forming G-quadruplexes.
• Neuronal pathogenesis in ATR-X models is linked to aberrant gene expression.

Purpose of the Study:

• Investigate the role of ATRX in regulating Xlr3b gene expression in the mouse brain.
• Elucidate the mechanism by which ATRX controls Xlr3b.
• Evaluate the therapeutic potential of targeting G-quadruplexes for ATR-X syndrome.

Main Methods:

• Genome-wide analyses in mouse and human cells to identify ATRX binding sites.
• Analysis of Xlr3b gene regulation, including DNA methylation and transcription.
• Assessment of dendritic mRNA transport and synaptic function in ATR-X model mice.
• Treatment of ATR-X model mice with 5-aminolevulinic acid (5-ALA).

Main Results:

• Atrx mutation leads to increased Xlr3b expression in the mouse brain.
• ATRX binds to G-quadruplexes in the Xlr3b gene's CpG islands, regulating expression via DNA methyltransferases.
• Overexpression of Xlr3b impairs dendritic transport of CaMKII-α mRNA, causing synaptic dysfunction.
• 5-ALA treatment reduces Xlr3b transcription and rescues synaptic plasticity and cognitive deficits in ATR-X mice.

Conclusions:

• ATRX regulates Xlr3b expression through G-quadruplex binding and epigenetic mechanisms.
• Xlr3b-mediated synaptic dysfunction contributes to ATR-X pathogenesis.
• Targeting G-quadruplexes with 5-ALA offers a potential therapeutic strategy for cognitive impairment in ATR-X syndrome.