Cloning and generation of reporter lines

For the generation of an interneuron‐specific reporter cell line, a reporter construct was inserted into the AAVS1 safe harbor locus in hESCs using TALEN technology, as described previously (Hockemeyer et al, 2011). To specifically label interneurons, we designed a human version of the mouse Dlx5/6 enhancer (mDlx), which had been shown to have interneuron specificity in murine and human hPSCs (Dimidschstein et al, 2016). We inserted the human Dlxi56 enhancer, driven by a minimal promoter, into the AAVS1 donor vector we had used previously using eGFP to monitor expression (Bagley et al, 2017). The following expression construct was inserted: 2xCHS4‐Dlxi56‐HBBminP‐Intron‐eGFP‐WPRE‐SV40‐2xCHS4. Sequence files and construct plasmid DNA can be obtained from the corresponding author upon request.

Nucleofection, selection of clones with correct insertion, and quality control were performed as described previously (Bagley et al, 2017). Cell clones with correctly targeted insertions were archived by freezing with Cell Banker 2 solution (Amsbio, cat. #11891).