Figure 4.

KLF4 Nuclear Export Occurs through an XPO1-Mediated Mechanism

(A) Immunofluorescence images of ESCs cultured for 6 and 12 hr without LIF/2i in the presence of 5 μg/mL leptomycin B (LMB), which inhibits XPO1-mediated nuclear export. Merged images display KLF4 in green, RNAPII-S5P in red, and DAPI in blue. Scale bars, 10 μm.

(B) Proximity ligation amplification (PLA) displays the interaction between KLF4/XPO1 and XPO1/ERK2 in ESCs and 6 hr after LIF/2i withdrawal. Images shown are single optical sections. Merged images display DAPI in blue and PLA in red. Bottom images display the grayscale PLA signal. Scale bars, 10 μm.

(C) KLF4 and ERK2 immunoprecipitation (IP) for undifferentiated ESCs and ESCs 6 hr after LIF/2i removal, probed with anti-ERK2 and anti-XPO1 (PD, pull-down). GAPDH levels reveal equal loading of the input.

See also Figure S4.