Fig. 3.

(a) Schematic representation of genomic organization of the UPB1 gene. UPB1 consists of ten exons encoding an open reading frame of 1152 bp (depicted in grey). The mutations identified to date in βUP deficient patients are indicated, with numbers corresponding to cDNA positions. (b) Expression of βUP mutants in HEK293 cells. Residual enzymatic activity of βUP mutants are expressed as percentages of wild-type βUP activity. For each construct, columns show mean values and standard deviations derived from at least three transfections. (c) Western blot analysis of HEK293 cells expressing wild-type and mutant βUP. Total cell protein (5 μg) was resolved by SDS-PAGE followed by immunoblotting against βUP and alpha-tubulin. (d) Native polyacrylamide gel electrophoresis of HEK293 cells expressing βUP protein (wild-type and mutants). Cell supernatants (5 μg) were subjected to 4–16 % blue native page, followed by western blot analysis using polyclonal anti-βUP antibody