Fig. 3. CEPsh glia support axon guidance in the nerve ring. (A-H) AWC axonal defects of adult C. elegans lacking ventral left and right CEPsh glia. Fluorescence images (A-D) and corresponding schematics (E-H) of AWC neurons expressing odr-1::RFP. (A,E) Mock-ablated animal. (B-D,F-H) AWC defects frequently observed in operated animals. In all panels, the reporter is also expressed in AWB axons. (J-Q) AWC axon defects observed in mls-2(ns156) adults. Fluorescence images (J-M) and corresponding schematics (N-Q) of AWC neurons expressing odr-1::RFP. (J,N) Wild-type AWC axon. (K-M,O-Q) AWC defects of mls-2(ns156) adults. In J-M, reporter is also expressed in AWB neurons. Similar defects are seen in vab-3(ns157) mutants and in AFD neurons of mls-2(ns156) and vab-3(ns157) animals. (I) Histogram depicting AWC, ADF and AFD axonal defects in animals of indicated genotype or in which CEPsh glia were ablated. VL/R+, expressing hlh-17::GFP in ventral left and right CEPsh glia. Others, lacking hlh-17::GFP in one or both ventral CEPsh glia. n, number of animals. Some mls-2(ns156) mutants fail to express AWC reporters. We only scored animals in which robust expression was evident. (R-U) DIC (R,T) and fluorescence (S,U) images of wild-type L1 animal (R,S) and an L1 with ablated ventral left and right CEPsh glia (T,U) expressing unc-119::GFP. The posterior pharyngeal bulb is circled. Arrowhead, nerve ring. Note the abnormal positioning and shape of the nerve ring in the ablated animal. (V) Mosaic studies of mls-2. Axonal defect +, AFD axon defect; axonal defect -, no defect; n, number of animals; transgene +, transgene present; transgene -, transgene absent.