DNA methylation regulates tissue-specific expression of Shank3

Area of Science:

• Neuroscience
• Epigenetics
• Molecular Biology

Background:

• SHANK3 is crucial for excitatory synapse function and implicated in 22q13 deletion syndrome.
• SHANK1, SHANK2, and SHANK3 are homologous genes involved in synaptic structure.
• Gene expression is often regulated by epigenetic mechanisms like DNA methylation.

Purpose of the Study:

• To investigate the role of DNA methylation in regulating the expression of SHANK3, SHANK1, and SHANK2.
• To determine if SHANK3 expression correlates with DNA methylation patterns across different tissues.
• To explore potential epigenetic control mechanisms for SHANK3.

Main Methods:

• DNA methylation analysis in human lymphocytes, brain cortex, cerebellum, and heart.
• Assessment of SHANK3 protein expression in hippocampal neurons following methionine treatment.
• Analysis of SHANK3 expression in HeLa cells after 5-Aza-2'-deoxycytidine treatment.

Main Results:

• SHANK3, but not SHANK1 or SHANK2, exhibited high DNA methylation in tissues with low/absent protein expression and unmethylation where expression was present.
• Methionine treatment reduced SHANK3 protein expression in hippocampal neurons.
• 5-Aza-2'-deoxycytidine treatment induced SHANK3 expression in HeLa cells.

Conclusions:

• A specific epigenetic control mechanism, involving DNA methylation, regulates SHANK3 expression.
• This epigenetic regulation appears specific to SHANK3 and not its homologues SHANK1 and SHANK2.
• Findings suggest DNA methylation is a key factor in controlling tissue-specific SHANK3 expression.