Fig. 1: KLF4 forms a condensed liquid phase in HEK 293T cells and BJ fibroblasts.

a Fluorescence microscopy images of DNA (Hoechst), mTurq fluorescent tag (top), and KLF4-mTurq (bottom) in HEK 293T cells. Nuclear mTurq distribution is diffuse whereas KLF4-mTurq forms biomolecular condensates. Similar results were obtained for >5 biological replicates. b HEK 293T cells (top) and BJ fibroblasts (bottom) expressing KLF4-mTurq exhibit diffuse distribution (left), irregular puncta (middle), or droplets (right; circularity > 0.8). Similar results were obtained for 3 biological replicates. c Fluorescence recovery after photobleaching (FRAP) of KLF4-mTurq droplets in BJ fibroblasts (top row) bleached at positions indicated by white arrows; right panel is a recovery curve (n = 8 droplets) and enlarged insets track one droplet (white square). FRAP of KLF4-mTurq puncta in HEK 293T cells (bottom row) bleached at positions indicated by white arrows and circle; right panel is a recovery curve (n = 6 punctate fields). Data are presented as mean values ± SD. d Fluorescence image time course of droplet fusion (at white arrows) in BJ fibroblasts. Fusion was verified with 3D z-stack images. e Fluorescence microscopy image of KLF4-mTurq puncta and droplets in HEK 293T cells before (left) and after (right) 1,6-hexanediol treatment. Nucleus outline in white dashes. Similar results were obtained for 2 biological replicates.