A Phylogenetic analysis of the relationships of chordate NGFR and NRADD genes. B The structure of the Ngfrb-, Nradd-, and Ngfrb/Nradd chimaeric-fusion proteins. Scissors indicate where the v2a sequence causes separation of the C-terminal free GFP from the remainder of each fusion protein. C During translation, the v2a sequence causes separation of the C-terminal free GFP from the remainder of each fusion protein so that the two protein fragments are initially present in a 1:1 ratio. The free GFP is then used as an internal control to assess the relative abundance of the N-terminal fusion protein fragment. D–F Comparison of the relative abundance of the N-terminal fragment of the Ngfrb- (D), Nradd- (E), and Ngfrb/Nradd chimaeric (F) -fusion proteins without (−) and in the presence of (+) γ-secretase DAPT. P-values are derived from two-tailed t-tests with Welch’s correction