Identification of the DN2b/3-specific Runx1 and GATA3 binding site at the Spi1 locus. (A) BM progenitors obtained from B6 mice were co-cultured on OP9-DLL1 for 5 or 14 d. Lin⁻CD45⁺CD25⁻Kit^hi+CD44⁺ DN1 cells and Lin⁻CD45⁺CD25⁺Kit^loCD44^lo DN2b/3 cells were sorted on days 5 and 14, respectively, and subjected to ChIP-seq analysis for Runx1 (Hosokawa et al., 2018b) and GATA3. Representative ChIP-seq tracks in DN1 and DN2b/3 cells around the Spi1 locus are shown with the conservation track. Previously reported cis-regulatory elements and a DN2b/3-specific Runx1 and GATA3 binding site are labeled with blue and magenta rectangles, respectively. Data are representative of two independent experiments. Chr2, chromosome 2. (B) Representative ATAC-sequencing tracks in DN1, DN2a, DN2b and DN3 cells around the Spi1 locus are shown (Yoshida et al., 2019). (C) The short interspersed nuclear element (SINE) and LINE element tracks around the Spi1 locus in mouse (mm10) are shown with the conservation track. A position for the DN2b/3-specific Runx1 and GATA3 binding site is labeled with a magenta rectangle.