Pycallingcards: an integrated environment for visualizing, analyzing, and interpreting Calling Cards data
Unraveling the transcriptional programs that control how cells divide, differentiate, and respond to their environments requires a precise understanding of transcription factors'(TFs) DNA-binding activities. Calling cards (CC) technology uses transposons to capture transient TF binding event at one instant in time and then read them out at a later time. This methodology can also be used to simultaneously measure transcription factor binding and mRNA expression from single cells CC and to record and integrate TF binding events across time in any cell type of interest without the need for purification. Despite these unique advantages, there has been a lack of dedicated bioinformatics tools for the detailed analysis of CC data. Here, we introduce Pycallingcards, a comprehensive Python module specifically designed for the analysis of single-cell and bulk CC data across multiple species. The package introduces two innovative peak callers, CCcaller and MACCs, enhancing the accuracy and speed of pinpointing TF binding sites from CC data. Pycallingcards offers a fully integrated environment for data visualization, motif finding, and comparative analysis with RNA-seq and ChIP-seq datasets. To illustrate its practical application, we have reanalyzed previously published mouse cortex and glioblastoma datasets. This analysis revealed novel cell-type specific binding sites and potential sex-linked TF regulators, furthering our understanding of TF binding and gene expression relationships. Thus, Pycallingcards, with its user-friendly design and seamless interface with the Python data science ecosystem, stands as a critical tool for advancing the analysis of TF function via CC data. Overall design: Calling Cards were transfected into k562 cells in multiple replicates. Transfected cells were selected with puromycin and bulk Calling Cards libraries were prepared.