MNX1 protein expression and chromatin interaction of the MNX1 gene with the ETV6 region in ChiPSC22^t(7;12) cells. (A) Western blot with an MNX1 antibody (left) and iPSC (blue) and HSPC (red) protein extracts from ChiPSC22^WT and ChiPSC22^t(7;12) sublines 14D7, 23G8, and 24C7. The MNX1 protein (asterisk) is only detected in HSPCs of ChiPSC22^t(7;12) sublines 14D7, 23G8, and 24C7. The common band at ∼120 kD results from an unknown protein cross-reacting with the MNX1 antibody. To demonstrate loading of equal protein amounts, the unstripped blot was reincubated with an antibody against β-actin (right). (B) Chromatin interactions analyzed by Hi-C seq in the genomic region flanking the translocation break point in the ChiPSC22^t(7;12) subline 24C7, either as iPSCs (top) or HSPCs (below). The neo-TAD is indicated by a black bar. ChIPseq data for CTCF and RAD21 in K562 were retrieved from the encode project (IDs ENCFF468HJA and ENCFF000YXZ). (C) Increased proximity between MNX1 and ETV6 in ChiPSC22t(7;12) subline 14D7–derived HSPCs compared with iPSCs. Representative STED images of FISH spots in 2 colors targeting MNX1 and ETV6 in iPSCs and HSPCs (left). Scale bars, 500 nm. 3D distances between the MNX1 and ETV6 signals (right). Red horizontal lines within boxes indicate medians; box limits indicate upper and lower quartiles. iPSCs, n = 154; HSPCs, n = 409, across 3 independent replicates. ∗P < .05, Wilcoxon rank-sum test.