Figure 7 from Phase Separation Mediates NUP98 Fusion Oncoprotein Leukemic Transformation

Abstract

<p>Additional leukemia-associated NUP98 FOs form nuclear puncta and transform lin<sup>−</sup> HSPCs. <b>A,</b> Schematic of NHA9 and three additional NUP98 FOs (NUP98–PRRX1, NUP98–KDM5A, and NUP98–LNP1). Numbers indicate the amino acid residue. Numbers above the schematic reflect NUP98 residues, whereas numbers beneath reflect the fusion partner's residues. <b>B,</b> Representative images of live lin<sup>−</sup> HSPCs expressing G-NUP98–PRRX1, G-NUP98–KDM5A, and G-NUP98–LNP1. EGFP empty vector and G-NHA9 are included for comparison. <b>C,</b> Average number of colonies per 2,000 cells for lin<sup>−</sup> HSPCs expressing negative control empty vector and NUP98 FOs. Data shown are mean ± SD from triplicate technical replicates of a representative experiment. <b>D,</b> Representative images of a fixed, nontransduced human CD34<sup>+</sup> (hCD34<sup>+</sup>) cell (top) and a NUP98–KDM5A PDX cell (bottom) stained with an antibody against NUP98. NUP98 is magenta, and DNA is blue. The heat map is a normalized representation of NUP98 fluorescence intensity across the PDX cell. <b>E,</b> Conceptual scheme illustrating how LLPS by NHA9 mediates the formation of aberrant transcriptional condensates in hematopoietic cells. NHA9 (top, left cell image) undergoes LLPS to form many small, chromatin-associated puncta that drive aberrant expression of <i>Hox</i> and other genes and transform hematopoietic cells. LLPS is driven by both homotypic and heterotypic interactions. Mutation of FG motifs (NHA9–21FGAA, bottom left) weakens both homotypic and heterotypic protein–protein interactions, yielding less numerous, larger, and less dense puncta that do not activate <i>Hox</i> gene expression or transform HSPCs. Mutation of residues in the HOXA9 homeodomain (HD; NHA9–ΔDNA, bottom right) weakens heterotypic interactions with DNA, yielding less numerous, larger, and more dense puncta that also do not induce the leukemogenic phenotype in HSPCs.</p>

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