(A) lim-6 controls cell identity markers in AVL and RIS, but not DVB. (B) nhr-67 controls additional neuron identity markers of GABAergic neurons. nhr-67(ot795) animals are not viable and otEx5999 is an extrachromosomal array that contains copies of the wild-type nhr-67 locus as well as an array marker (unc-47prom::mChOpti). Animals that either contain this array or do not contain it were scored for mutant phenotypes at the L1 stage. (C) tab-1 controls the expression of RMEL/R identity markers. (D) ceh-10 controls the expression of RMED identity markers. (E) unc-4 controls the expression of the AVF identity marker bicd-1. (A–E) plain arrow head indicates a neuron presence and empty arrow head its absence (Scale bar = 10 μm; Fisher exact test, ***p<0.001, compared to wild type; when not noted, not significant; for expression in RMEs or AVFs statistics were performed only on the category 4RMEs or 2AVFs) (F) Summary of known gene regulatory programs in GABA producing neurons (GABA uptake neurons are not shown). ‘?’ indicates the regulatory relationship is just extrapolated from the effect of the transcription factor on GABA pathway genes. Already previously reported were the effect of lim-6 on non-GABA pathway genes in RIS and AVL, on unc-25 in DVB (Hobert et al., 1999; Tsalik et al., 2003), the effect of nhr-67 on unc-47 (Sarin et al., 2009), the effect of unc-30 on unc-25 and unc-47 (Eastman et al., 1999), the effect of ceh-14/ceh-17 on let-23, plc-3, ver-3, ida-1 and flp-7 (Van Buskirk and Sternberg, 2010).