Figure 2: SSEA-4 is expressed in cells of human testis that have an active POU5F1 promoter. (A): Stably transfected human germ cells with a GFP reporter plasmid under the control of the POU5F1 promoter. Cells expressing GFP (green, shown by the arrows) were used to assay the expression of SSEA-4 in (B). Nuclei are stained by DAPI (blue). Scale bars = 5μm. (B): qRT-PCR analysis of the expression of POU5F1, cMYC and SSEA-4 genes in the following cell populations: ‘Testis’ is whole human testis cell suspension, ‘SSCs’ are the POU5F1 promoter-GFP expressing cells cultured under SSC maintenance conditions, ‘gPS’ are the germline pluripotent cells generated when the GFP expressing cells are cultured under de-differentiation conditions for 5 weeks, ‘iPSCs’ are the IMR90-4 induced pluripotent stem cells used as a control. The different samples were assayed in triplicates and normalized to GAPDH. Asterisks show significant differences in mRNA levels, as determined by t-test analysis (p<0.05).