Expression of FORS1 antigen after DNA transfection of the selected expression constructs into COS1(B3GALNT1) cells analyzed by FACS cytometry. After DNA transfection of COS1(B3GALNT1) with a variety of expression constructs and a vector expressing mRFP, cells were immunostained using anti-FORS1 antibody, followed by FACS analysis. The percentages of FORS1-positive cells for each construct and for all 3 independent experiments are depicted as open circles. Their mean ± standard deviation is written in numbers and represented on the graph as red bars (horizontal for the mean and vertical for the standard). The construct names are shown under the x-axis. Two-tailed, homoscedastic Student t tests comparing each set of data to the empty vector set were performed, and P < .05 is shown.