Figure 1. Glia initiate male-specific gene expression at sexual maturity.

(A) Scanning electron micrographs of the heads of an adult hermaphrodite (left) and male (right). Nose tips are at top. Chemosensory cilia protrude through open cuticle pores associated with the six inner labial (IL) sense organs in both sexes (gray arrowheads; three on each side of the head) and four cephalic (CEP) sense organs in the male (right; red arrows; two on each side of the head). Mechanosensory cilia of the hermaphrodite CEP sense organs are embedded beneath a closed sheet of cuticle and appear as a bump under the surface, with no pore (left; blue arrows). (B) Schematic of C. elegans sense organs showing socket (so) and sheath (sh) glial cells wrapping neuronal endings. Cuticle aECM forms a closed sheet (left) over sense organs with a single mechanosensory neuron (outer labial, OL; deirids, ADE/PDE) or a ~200 nm open pore (right) over sense organs with a mechanosensory and chemosensory neuron pair (inner labial, IL; rays and hook of male tail). Importantly, cuticle aECM of the CEP sense organ undergoes sex-specific remodeling from a closed sheet in hermaphrodites to an open pore in adult males. (C, D) Expression of grl-18pro:GFP in (C) hermaphrodite and (D) male head glia. Nose is up. (E, F) Fraction of hermaphrodites (n=48) and males (n=50) expressing grl-18pro:GFP at third and fourth larval stages (L3, L4) and the 1-day adult stage (Ad) in (E) ILso glia and (F) CEPso glia. The same animals were followed and scored at each stage. Error bars, standard error of the mean (SEM). See also Figure S1.