Fig. 1: Enzymatic synthesis and synaptic release of GABA by defined factors.

a Neurogenesis was induced in H1-ES cells by lentiviral Ngn2 expression, co-infected with additional viruses encoding vGAT, GAD65, and/or GAD67; neurons were co-cultured with mouse glia and analyzed at day 56–60. b An example image of Ngn2-induced human neurons (cyan arrowheads) co-transduced with V57 factors, immunolabeled for MAP2, Synapsin, and stained for nuclear DAPI (white arrowheads). The MAP2-negative and DAPI-stained population indicate co-cultured mouse glial cells. Inset, dotted box magnified on right. c, d Sample traces of sPSCs recorded from indicated conditions c, and normalized cumulative frequency of τ-decays d for fast vs. slow (blue vs. red arrowheads) events. Insets in d, example waveforms of 10 scaled and overlaid sPSCs (light shade) with corresponding averages (dark shade) for control (top) vs. V57 (bottom). e, f Average frequency (left) and amplitude (right) of sPSC events with fast (e, τ-decay < 10 ms) vs. slow (f, τ-decay > 10 ms) decay kinetics, as recorded from human neurons expressing indicated factor combinations. g, h Representative traces g and cumulative histogram of τ-decay h of sPSCs recorded from Ngn2-neurons co-expressing V57 factors, before (Ctrl) and after acute treatments with PTX and/or CNQX (as annotated). i–k. Cumulative probabilities (left) and average values (right) of sPSC half-width (i), amplitude (j), and event frequency (k), measured in the absence (Ctrl) or presence of inhibitors, PTX, CNQX, or both PTX + CNQX. All data are presented as means ± SEM, with number of cells patched / independent batches. Individual data-points are provided as color-matched open circles. For panels e, f, statistical significance was evaluated by Kruskal-Wallis test paired with post-hoc nonparametric Mann-Whitney U-test using Bonferroni correction (see Source Data). For i, j, k, Skewness and Kurtosis values (-2 >≈  and ≈ < 2) suggested normal distribution, as statistical significance was weighed by two-tailed, unpaired, Student’s t-test, with ***P < 0.005; **P < 0.01; *P < 0.05; ns = not significant, P > 0.05. Multiple groups in panel k were also compared by an analysis of variance (one-way ANOVA) paired with post-hoc Tukey-Kramer test, and corresponding P-values were reported.