GFP expression decreases upon differentiation towards pancreatic progenitor cells.

<p>(A) The mRNA expression of OCT4 was measured during the differentiation of CyT49 cells. Day 0 represents undifferentiated hESC cells, Days 1–3 are cells becoming definitive endoderm, Days 4–6 are cells becoming posterior foregut, Day 9 are pancreatic endoderm cells and Day 12 are pancreatic progenitors and endocrine cells. (B) CyT49 cells were fixed with 4% PFA, permeabilized in 0.5% triton-X, stained using rabbit anti-OCT4 antibodies followed by FITC-conjugated donkey anti-rabbit antibodies. The number of FITC+ cells was measured using a BD FACSCalibur during several days of the differentiation protocol. The number of GFP⁺ cells was measured using native eGFP fluorescence and a BD FACSCalibur in OCT4-2 (C), OCT4-3 (D) and OCT4-28 (E) fixed cells. n≥3.