Abstract: Objective To examine the genome-wide identification of PU. 1 binding sites and target genes before and after hemin-induced differentiation in K562 cells. Methods K562 cells were treated with hemin for 72 h to induce cell differentiation. High-throughput sequencing was performed following chromatin immunoprecipitation with PU. 1 antibody in untreated and hemin-treated cell groups. The binding sites of PU. 1 in K562 cells before and after differentiation were analyzed by bioinformatics. Gene annotation, gene function analysis, KEGG pathway analysis and target genes prediction were performed. Results The results showed that there were 3 107 and 1 897 binding sites of PU. 1 before and after differentiation respectively. Among them, 843 binding sites were identified in both untreated and differentiated K562 cells. KEGG pathway analysis showed that the NF-κB signaling pathway, growth hormone synthesis, secretion and transport pathway, and MAPK signaling pathway were the unique signaling pathways related to PU. 1 binding after differentiation. Totally, 1 210 PU. 1 binding sites changed during differentiation, corresponding to 179 target genes. Moreover, the PU. 1 target genes related to differentiation included globin genes, autophagy-related genes, microRNA and non-coding RNA, and transcription factors. Motif analysis showed that PU. 1 tended to bind a specific ACTTCC sequence. Conclusion The genomic binding sites of PU. 1 changed significantly after hemin-induced differentiation in K562 cells. Our study provided a basis for further research on the function of PU. 1 in hematopoietic cell

Key words: K562 cell, differentiation, PU. 1, ChIP-seq