Purpose: Cohesin is an important structural regulator of the genome. Whether cohesin HEAT repeat accessory proteins PDS5A and PDS5B differentially contribute to cohesin function remains unclear. The purpose of this study is to interrogate how PDS5A and PDS5B affect cohesin localization and gene expression in mouse embronic stem cells (mESCs) Method: Genome wide binding patterns of PDS5A, PDS5B, and cohesin in wildtype cells as well as in PDS5 CRISPR/Cas9 genome edited knockout cells were assessed via chromatin immunoprecipitation followed by high throughput sequencing (ChIP-seq). The redundancy of the PDS5 subunits was addressed by using siRNA against PDS5B in a PDS5A-knockout background. Overall design: ChIP-seq was performed in wildtype mESCs in duplicate for PDS5A, PDS5B, and RAD21. ChIP-seq was performed in CRISPR-Cas9 genome edited PDS5 deletion mESCs in duplicate for the reciprocal PDS5 and RAD21. ChIP-seq was performed in wildtype and PDS5A-KO cells after being treated with either siGLO transfection control or siPds5b.