Nuclear position and local acetyl-CoA production regulate chromatin state

Area of Science:

• Developmental Biology
• Epigenetics
• Molecular Biology

Background:

• Histone acetylation is a key epigenetic mechanism regulating gene expression, cellular functions, and cell fate.
• Understanding spatial patterns of histone acetylation in developing tissues is crucial for deciphering developmental processes.

Purpose of the Study:

• To investigate the spatial distribution and regulatory mechanisms of histone acetylation in the Drosophila wing disc epithelium.
• To identify the metabolic pathways and cellular features associated with specific histone acetylation patterns.

Main Methods:

• Analysis of histone acetylation marks (H3K18ac, H4K8ac, total lysine acetylation) in Drosophila wing discs.
• Tracking nuclear position within the epithelial layers.
• Measuring levels of acetyl-CoA synthase and fatty acid β-oxidation.
• Inhibiting fatty acid β-oxidation and assessing its impact on histone acetylation and gene expression.

Main Results:

• Increased levels of H3K18ac, H4K8ac, and total lysine acetylation were observed in the outer rim of the Drosophila wing disc.
• Histone acetylation levels, particularly H3K18ac, correlated with nuclear position, being higher in surface-associated nuclei.
• Surface nuclei showed elevated acetyl-CoA synthase activity, suggesting a role in providing acetyl-CoA for histone acetylation.
• Fatty acid β-oxidation was identified as the primary carbon source for histone acetylation in the rim, and its inhibition reduced H3K18ac levels near developmental genes.

Conclusions:

• A distinct pattern of histone acetylation marks the outer rim of the Drosophila wing disc, influenced by nuclear position and metabolic activity.
• Nuclear position and metabolic pathways, specifically fatty acid β-oxidation, play critical roles in regulating histone acetylation and subsequently gene expression during development.
• This study reveals a physical and metabolic signature on epithelial tissues that impacts gene expression during development.