KAS-CUT&Tag for direct mapping of transcription bubbles.

Area of Science:

• Molecular Biology
• Genetics
• Epigenetics

Background:

• RNA Polymerase II (Pol II) transcription creates dynamic transcription bubbles.
• Current methods for mapping transcriptional activity in vivo are indirect.
• Directly mapping transcription bubbles is crucial for understanding gene regulation.

Purpose of the Study:

• To introduce KAS-CUT&Tag, a novel method for directly mapping transcription bubbles.
• To analyze the distribution and enrichment of transcription bubbles across genes.
• To investigate the colocalization of regulatory factors with transcription bubbles.

Main Methods:

• KAS-CUT&Tag combines N3-kethoxal labeling of exposed guanines with CUT&Tag.
• This method directly maps transcription bubbles in vivo.
• Analysis of bubble density and enrichment at specific genomic locations and in relation to histone modifications.

Main Results:

• Transcription bubble density varies across Pol II-bound genes, including start sites, gene bodies, and termination sites.
• Bubbles are enriched at genes with H3K36me3 modification and U2AF2, with highest enrichment at replication-coupled histone genes.
• KAS-CUT&Tag detected NPAT colocalization with Pol II at the Histone Locus Body.

Conclusions:

• KAS-CUT&Tag provides a direct method for mapping transcription bubbles and associated regulatory interactions.
• The study reveals specific patterns of transcription bubble distribution and enrichment.
• Findings suggest NPAT interacts with Pol II at transcription bubbles, particularly at histone genes.