Fig. 1. The repressible Q binary system functions effectively in C. elegans.

(a) Schematic of the Q system. X indicates transgene. Black circles at the bottom indicate quinic acid.

(b) Schematic diagram of VA and DA motor neurons in the ventral nerve cord (VNC). The boxed region is magnified to show VA9 and VA10 neurons in green and DA6 and DA7 in magenta. (c-n) The micrographs show transgenic worms (L3 larvae) expressing the indicated transgenes, with or without treatment with quinic acid for 24h. An overview of the VNC (c, g, k) and magnification of the boxed region (d-n) are shown. GFP expression is shown green, mCherry expression is shown in magenta. P, promoter; SL2, trans-spliced leader sequence. White asterisks denote ectopic gut fluorescence caused by SL2∷mCherry cassette (X. Wei and K. Shen, unpublished results). Yellow asterisks denote occasional ectopic gut fluorescence due to QUAS∷GFP. Scale bars, 20 μm. (o) Quantification of labeling efficiency in (c-n). Late L3 or early L4 stage larvae were scored (n>200 for each strain). Animals are divided into 3 categories: None (no A-type neurons labeled), Full-labeling (all A-type neurons labeled) and Partial-labeling (between None and Full-labeling). (p) Quantification of Dpy rescue efficiency with Q system in Supplementary Figure 4. n =40 for each group; **P ≤0.0001 (versus wild type animals), χ² test. Animals with a body length longer than 972 μm are scored as wild type. Animals with a body length shorter than 972 μm are scored as Dpy mutants.