Figure 4. Hox genes – like unc-3 – control the expression of MN subclass-specific genes along the A-P axis.

(A–B) The expression of the subclass-specific markers unc-129 (DA1-7/DB) and del-1 (VA1-11/VB) is significantly affected in lin-39 mab-5 double mutants, as well as in animals lacking ceh-20, C. elegans PBX homolog known to function as Hox co-factor. Quantification of the number of MNs expressing the gfp reporter (bright or dim) is provided at the bottom. Effects on reporter expression are milder in Hox null mutants when compared to unc-3 null mutants. Error bars represent standard deviation (STDV). ***p value < 0.001. N > 20 animals. (C–D) The posterior Hox gene egl-5/Abd-B/Hox9-Hox13 controls subclass-specific genes (itr-1, glr-4, mig-13, flp-18) expressed in the most posterior member of the DA (DA9) and VA class (VA12). Effects on reporter expression are milder in egl-5 null mutants when compared to unc-3 null mutants. Similar effects were observed for multiple egl-5 loss-of-function alleles (n945, u202, tm4746). A dotted white line marks the limit of the intestinal cells. (E) Quantification (percentage of animals) is provided with grey bars representing very dim gfp expression in the respective neuron, while black bars represent bright gfp expression. ***p value < 0.001. N > 20 animals.

DOI: http://dx.doi.org/10.7554/eLife.25751.008

Figure 4—figure supplement 1. Analysis of acetylcholine pathway gene expression in Hox mutants and ceh-20/Pbx analysis.

(A) The expression of the acetylcholine (ACh) pathway gene unc-17/VAChT is not affected in cholinergic ventral nerve cord MNs of lin-39(n1760)mab-5(e1239) double mutant animals. Quantification is provided on the right. N.S, not statistically significant differences. N = 15. Expression was assessed using a transcriptional reporter for unc-17/VAChT (unc-17 ^prom::gfp). (B) Expression of the ACh pathway gene cho-1/ChT1 was mildly affected in lin-39(n1760);mab-5(e1239) double mutant animals because the cho-1 ^fosmid mChOpti::H2B fosmid-based reporter (unlike unc-17 ^prom::gfp) also labels six MNs of the VC class, which are not generated in lin-39(n1760);mab-5(e1239) mutants. N = 15. ***p value < 0.001. Error bars represent standard deviation (STDV). (C) The expression of unc-17/VAChT is not affected in DA9 and VA12 neurons of egl-5(n945) mutant animals. Quantification is provided on the right. N = 25. (D) The expression of ceh-20 in the DA9 neuron at the L4 stage is confirmed using glr-4^prom::tagRFP as a DA9-specific marker. (E) The expression of the DA9-specific markers itr-1, glr-4, and mig-13 is unaffected in ceh-20(ok541) mutants (L4 stage). N = 10.

DOI: http://dx.doi.org/10.7554/eLife.25751.009