Figure 3: Immobilized LIF promotes Oct-4 expression and chimera formation in a dose-dependent manner.
From: Functional immobilization of signaling proteins enables control of stem cell fate
(a) Representative histograms showing Oct-4 expression for cells cultured for 72 h on 75 ng/cm2 immobilized LIF on POMA or POMA-matrix. Red lines on each plot represent Gaussian fits of Oct-4+ (right peak) and Oct-4− (left peak) subpopulations. The blue lines are the overall fit for both populations. (b) Concentration-dependent expression of Oct-4 in mESCs cultured for 72 h on POMA-immobilized LIF, or matrix-physisorbed LIF. Diffusible LIF was replaced during medium change every 24 h (results obtained from 5 × 103–1 × 104 single-cell measurements; error bars, s.e.m.; *P < 0.05, Student's t-test for respective conditions). (c) Oct-4 expression in cells cultured in the absence of LIF, the presence of indicated amount of LIF immobilized covalently to POMA and diffusible LIF over time. Error bars, s.d. (d) Chimeric mice generated from cells cultured and passaged 6–8 times on POMA substrates with covalently attached LIF (8 ng/cm2), hydrolyzed POMA with diffusible LIF and tissue culture plastic with diffusible LIF (10 ng/ml each). All substrates were overlaid with gelatin to facilitate cell attachment.
