Description

In C. elegans hermaphrodites, sto-3 promoter has been previously shown to drive gene expression in RIBL/R neurons and in three unidentified non-neuronal cells in the tail (Turek et al., 2016). (A) We have found that in C. elegans males, in addition to RIBL/R, two pairs of bilaterally-symmetrical tail neurons show strong Psto3::wrmScarlet expression (wrmScarlet is a codon-optimized version of mScarlet (El Mouridi et al., 2017)). These neurons send their processes to rays 4 and 8 of the male tail. In the figure, right lateral aspect is shown; arrows indicate rays containing processes expressing Psto3::wrmScarlet. (B) All rays in the male tail are innervated by A and B type neurons (Sulston et al., 1980). To identify which neuron type expresses the sto-3 reporter, we have crossed Psto3::wrmScarlet transgenic males with a Ppkd-2::GFP reporter strain MT11318, which expresses GFP in the B-type neurons of rays 1-5, 7-9 and not in the A-type neurons (Barr and Sternberg, 1999). In the F1 cross-progeny males, which also carried the ceh-30(n3714) mutation in the background, Psto-3::wrmScarlet expression is colocalized with Ppkd-2::GFP for both pairs of ray neurons expressing Psto-3::wrmScarlet. This indicates that sto-3 is expressed in the R4BL/R and R8BL/R ray neurons. Left lateral aspect; arrows point at the cell bodies of Psto3::wrmScarlet-expressing neurons.