Cell-type-specific profiling of protein-DNA interactions without cell isolation using targeted DamID with...

Area of Science:

• Molecular Biology
• Genomics
• Developmental Biology

Background:

• Cell-type-specific profiling is crucial for understanding multicellular organism development and function.
• Existing methods for profiling DNA-binding proteins often require cell isolation or are limited in resolution.
• Targeted DamID (TaDa) was previously developed for genome-wide, cell-type-specific profiling in vivo.

Purpose of the Study:

• To describe substantial modifications and additional applications for the Targeted DamID (TaDa) protocol.
• To adapt TaDa for increased speed, throughput, and compatibility with next-generation sequencing.
• To enable cell-type-specific identification of transcribed genes using RNA polymerase II profiling.

Main Methods:

• Utilizes the GAL4 system in Drosophila for temporal and spatial control of Dam-fusion protein expression at low levels.
• Implements modifications to the core DamID technique to enhance sample processing speed and throughput.
• Adapts the protocol for preparation of sequencing libraries compatible with next-generation sequencing technology.

Main Results:

• The modified TaDa protocol is robust, reproducible, and highly sensitive.
• TaDa requires no cell-sorting, cross-linking, or antisera, generating binding profiles from as few as 10,000 induced cells.
• Genome-wide binding profiles of RNA polymerase II (Pol II) can be generated, enabling cell-type-specific identification of transcribed genes.

Conclusions:

• The enhanced TaDa protocol offers a powerful, efficient, and sensitive method for cell-type-specific profiling of DNA- and chromatin-binding proteins.
• TaDa facilitates the study of cell-fate specification and cellular function in a genome-wide, cell-type-specific manner.
• The protocol is adaptable to other organisms with inducible expression systems, with the entire procedure completable within 5 days post-transgenic animal generation.