Targeted DamID detects cell-type-specific histone modifications in intact tissues or organisms

Area of Science:

• Epigenetics
• Developmental Biology
• Genomics

Background:

• Histone modifications are crucial for gene regulation, cell differentiation, and disease processes.
• Existing methods for profiling histone modifications are often limited to dissociated cells and specific tissue types.

Purpose of the Study:

• To adapt and validate Targeted DamID (TaDa) for cell-type-specific genome-wide profiling of histone modifications in intact tissues and organisms.
• To demonstrate the versatility of the modified TaDa approach across diverse model systems and developmental stages.

Main Methods:

• Fusion of chromatin-binding proteins or single-chain antibodies to Dam methylase for targeted DNA adenine methylation.
• Application of the modified TaDa technique to profile histone marks (H3K4me3, H3K9ac, H3K27me3, H4K20me1) in vivo.
• Testing the method in Drosophila neural stem cells, developing mouse brains, and Xenopus embryos during gastrulation and neurulation.

Main Results:

• Successful in vivo profiling of H3K4me3, H3K9ac, H3K27me3, and H4K20me1 in Drosophila neural stem cells.
• Mapping of cell-type-specific H3K4me3, H3K9ac, and H4K20me1 distributions in the developing mouse brain.
• Demonstration of H3K4me3 profiling during Xenopus development using RNA injection at the 1-cell stage.

Conclusions:

• The adapted TaDa method enables cell-type-specific chromatin profiling of histone modifications in intact tissues and whole organisms.
• This versatile technique is applicable across diverse model systems, facilitating the study of epigenetic regulation during development and disease.