KAS-pipe2: a flexible toolkit for exploring KAS-seq and spKAS-seq data

Kethoxal-assisted ssDNA sequencing (KAS-seq) is gaining popularity as a robust and effective approach to study the dynamics of transcriptionally engaged RNA polymerases through profiling of genome-wide single-stranded DNA (ssDNA). Its latest variant, spKAS-seq, a strand-specific version of KAS-seq, has been developed to map genome-wide R-loop structures by detecting imbalances of ssDNA on two strands. However, user-friendly, open-source analysis pipelines for KAS-seq data are still lacking. Here we present KAS-pipe2 as a flexible and integrated toolkit to facilitate the analysis and interpretation of KAS-seq data. KAS-pipe2 can perform standard analyses such as quality control, read alignment, and differential RNA polymerase activity analysis. In addition, KAS-pipe2 introduces many novel features, including, but not limited to: calculation of transcriptional indexes, identification of single-stranded transcribing enhancers, and high-resolution mapping of R-loops. We use benchmark datasets to demonstrate that KAS-pipe2 provides a powerful framework to study transient transcriptional regulatory programs. KAS-pipe2 is available at https://github.com/Ruitulyu/KAS-pipe2.