Figure 2.

The effect of the passport sequence on subcellular localization of recombinant EPO

(A) Immunocytochemistry of HA-EPO and FLAG-EPO-PS expressed in Expi293F cells. The transfected cells were treated with 4% paraformaldehyde solution in PBS, incubated with PBS containing 3% fetal bovine serum and 0.1% Triton X-100, then stained with anti-FLAG, anti-HA, and anti-GM130 antibodies as primary antibodies, and Alexa Fluor 488-conjugated anti-mouse IgG (green), Alexa Fluor 555-conjugated anti-rat IgG (red), and Alexa Fluor 350-conjugated anti-rabbit IgG (blue) as secondary antibodies. Scale bar: 5 μm.

(B) Quantification of colocalization based on Fisher Z-transformed values, which were reconverted to Pearson’s correlation coefficient values (r). Data represent the means of twenty cells. Error bars indicate SEM. Statistical significance was assessed by unpaired t test: ∗∗p < 0.001.