Demonstration of CUT&RUN motif footprint analysis using key blood progenitor transcription factors

We introduce CUT&RUNTools (https://bitbucket.org/qzhudfci/cutruntools/) as a flexible, general pipeline for facilitating the identification of chromatin-associated protein binding and genomic footprinting analysis from antibody-targeted CUT&RUN primary cleavage data. CUT&RUNTools extracts endonuclease cut site information from sequences of short read fragments and produces single-locus binding estimates, aggregate motif footprints, and informative visualizations to support the high-resolution mapping capability of CUT&RUN. We illustrate the functionality of CUT&RUNTools through analysis of CUT&RUN data acquired for GATA1, a master regulator in erythroid lineage cells. Results were compared initially to published GATA1 ChIP-seq data for cells under the same conditions. We performed de novo analysis of CUT&RUN peaks to retrieve not only GATA1's primary motif, but also the GATA1-TAL1 composite motif, and co-factor motifs GCCCCGCCTC, CMCDCCC, and RTGASTCA that correspond to SP1, KLF1, and NFE2 co-factors. Cofactor binding was verified by independent TAL1 and KLF1 CUT&RUN, and other ChIP-seq experiments. CUT&RUNTools also generated base-pair resolution motif footprint for sequence-specific binding factors, and located likely direct binding sites by quantifying log-odds of binding scores. Overall, CUT&RUNTools should enable biologists to realize advantages of cleavage data provided by CUT&RUN, and make high-quality footprinting analysis accessible to a broad audience. Overall design: We performed CUT&RUN using GATA1, TAL1, and KLF1 antibodies in primary human stem/progenitor CD34+ cells after 7 days of erythroid differentiation, and in erythroid progenitor HUDEP2 cells followed by 4 days of erythroid differentiation.