FIG. 1.

N-terminal sequences of Usp-Δ_SPNuc and Δ_SPUsp-Δ_SPNuc fusion proteins. Sequences derived from Usp45 or from Δ_SPNuc (i.e., C-terminal 155 amino acids of Nuc) are shown in shaded or white boxes, respectively. The solid arrow indicates the Usp45 signal peptide cleavage site (61). The dashed arrow indicates the secondary site of proteolysis, which results in the NucA form (i.e., C-terminal 147 amino acids of Nuc) (30). The dashed lines joining Usp-Δ_SPNuc and Δ_SPUsp-Δ_SPNuc indicate the region of the former fusion which is absent in the latter.