Figure S2. HLH-3 is mostly dispensable for neurogenesis. Related to Figure 2. (A) List of the neurotransmitterreporter transgenes used to examine neurogenesis in
hlh-3 mutants. (B) The I4 neuron expresses a reporter transgenefor the glutamate transporter EAT-4 and might be glutamatergic (arrows and insets). (C) The other five MS-derivedneurons are generated normally in
hlh-3(
n5469) mutant animals (n=40). The glutamatergic reporter transgenePeat-4::
eat-4::mCherry is expressed in I4 and I6 in only 10% (for I4) and 60% (for I6) of the wild-type animalsexamined. (D-I) HLH-3 and Mediator specifically promote I4 neurogenesis and are likely dispensable for mostectodermal neurogenesis. The generation of (D) glutamatergic (wild type: 78.1 1.0, n=10;
hlh-2;
hlh-3: 77.0 0.6, n=16;
hlh-3;
dpy-22: 77.8 0.4, n=15), (E) cholinergic (wild type: 116.3 0.9, n=13;
hlh-2;
hlh-3: 115.5 1.0, n=15;
hlh-3;
dpy-22: 115.7 0.9, n=17), (G) dopaminergic (wild type: 7.9 0.1, n=19;
hlh-3: 8.0 0, n=20;
hlh-2;
hlh-3: 8.0 0, n=19), (H) tyraminergic/octopaminergic (wild type: 4.0 0, n=20;
hlh-2;
hlh-3: 4.0 0.1,n=20;
hlh-3;
dpy-22: 4.0 0.1, n=20), and (I) serotonergic (wild type: 4.0 0, n=20;
hlh-3;
dpy-22: 4.0 0.1,n=20;
hlh-3: 4.2 0.1, n=20) neurons is normal in
hlh-3 single and double mutants. The generation of (F)GABAergic (wild type: 18.8 0.1, n=25;
hlh-2;
hlh-3: 17.5 0.3, n=25;
hlh-3;
dpy-22: 17.5 0.2, n=25,P<0.001) neurons in
hlh-3 double mutants is mildly reduced. We were unable to examine cholinergic neurons inhlh-3;
dpy-22 double mutants, because the cholinergic reporter transgene is tightly linked to
dpy-22. In (I) we did notscore the serotonergic HSN neurons, which are generated but fail to differentiate normally in
hlh-3 mutants and donot express the Ptph-1::gfp reporter transgene [S1]. The slightly higher numbers of serotonergic neurons in
hlh-3mutants result from partial defects in the cell deaths of the sister cells of the serotonergic NSM neurons [S2] (I). Alldata represent mean s.e.m. ***, P<0.001 by student's t-test. Scale bars, 20 um.