Immunofluorescence experiments were performed essentially as described (Pang et al., 2011). Briefly, cultured iN cells were fixed in 4% paraformaldehyde in PBS for 20 min at room temperature, washed three times with PBS, and incubated in 0.2% Triton X-100 in PBS for 10 min at room temperature. Cells were blocked in PBS containing 10% goat serum for 1 hr at room temperature. Primary antibodies were applied overnight, cells were washed in PBS for three times and blocked with 10% goat serum for 15 min, secondary antibodies were applied for 1 hr. Transplanted iN cells in mouse striatum were analyzed by immunofluorescence staining after mice were transcardially perfused with saline followed by 4% paraformaldehyde. After overnight post-fixation, brains were removed, cryoprotected in 30% sucrose, and cut in 40 μm thick coronal sections. Free-floating sections were washed in PBS, incubated with PBS containing 0.25% Triton X-100 and 5% FBS for 1hr and stained overnight with primary antibodies. Following washes, sections were incubated with secondary antibodies for 2 hrs, washed, mounted on glass slides and coverslipped. For antibody details, see Supplementary Methods.
