Iterative assay for transposase-accessible chromatin by sequencing to isolate functionally relevant neuronal subtypes

Area of Science:

• Neuroscience
• Genetics
• Molecular Biology

Background:

• The Drosophila brain has numerous cell types, making precise genetic targeting challenging.
• Existing transgenic lines often lack specificity, expressing in multiple cell types without prior knowledge of expression patterns.

Purpose of the Study:

• To develop an iterative method for creating cell type-specific genetic tools for neuronal identification and manipulation in Drosophila.
• To refine transgene expression for precise targeting of neuronal subsets.

Main Methods:

• Developed an iterative assay for transposase-accessible chromatin (ATAC) approach.
• Used open chromatin regions (OCRs) enriched in neurons to drive initial transgene expression.
• Performed a second round of ATAC-seq on selected neuron subsets to identify further enriched OCRs for expression refinement.

Main Results:

• The ATAC-based approach successfully restricted transgene expression to specific neuron subsets.
• Iterative refinement using ATAC-seq enabled progressively narrower targeting of neuronal populations.
• Identified neurons associated with sleep behavior using this refined targeting method.

Conclusions:

• The iterative ATAC approach is effective for developing highly specific genetic tools in Drosophila.
• This method allows for the continued refinement of transgene expression for precise cellular targeting.
• The approach is broadly applicable to other cell types and organisms for genetic research.