Definitive endoderm derived from culturing human embryonic stem cells (HUES4) with Inhibin beta a ( ab50051 ) and Wnt3a ( ab81484 ) was further differentiated to gut tube endoderm as described in Kroon et al, Nat Biotechnol. (2008). KGF (ab9601) was added to the media to direct differentiation towards gut tube endoderm. This image was taken 3 days after addition of KGF, where the gut tube endoderm marker TCF2 ( ab59118 in green) is present. Dapi staining is shown in blue. Magnification: 200x. Negative controls of fluorescently conjugated secondary antibodies only showed no staining.