Expr14956

Strong endu-2 expression was detected in the intestine, which is consistent with a previous analysis using a multi-copy translational fusion GFP reporter (Ujisawa et al., 2018). However, no detectable fluorescence was seen in the germline.

Expr15497

Another transgenic reporter expressing 3xFlag::ENDU-2::EGFP was expressed strongly in the intestinal and also weakly in some head neurons, muscle cells in the head region, and anal depressor muscle cells, corroborating the report from Ujisawa et al.. We speculate that the N-terminal 3xFlag fusion may prevent secretion by impairing binding of the secretion signal peptide by signal recognition particle (SRP), thus allowing detection of the weak expression in the muscles and neurons.

Expr15496

We observed ENDU-2::EGFP protein in the cytoplasm of intestine, somatic gonad, and coelomocytes in both endu-2::EGFP transgenic (translational reporter) and the CRISPR/Cas9 EGFP knock-in strains. Unlike suggested in the study of Ujisawa et al., we did not detect ENDU-2::EGFP in the musculature or in the neurons. Instead, we noticed extracellularly localized ENDU-2::EGFP, such as in the interspace between uterine wall and embryos, suggesting that ENDU-2 may be a secreted protein.