FIGURE 6: Role of polyamine subtypes and their modification in the targeting of ODC.

(A) Western blot analysis comparing steady state levels of Oaz1 and ODC in either the wild type or a strain lacking spermine synthase (spe4Δ), grown with or without polyamine supplementation as indicated. Cells were transformed with plasmids expressing 2xmyc-Oaz1 from an in frame version of the OAZ1 gene, and with a plasmid encoding ODC-2xHa. The graph shows the results of a quantification of myc (upper part) and Ha signals (lower part) normalized to the Cdc11 loading control. Levels are given relative to the respective levels of the same proteins in cells grown without polyamine addition, which was set to 100%. Error bars, s.d.; n = 3.

(B) Acetylation of spermidine inhibits its binding to antizyme. In vitro binding assay showing the competition between [³H]-spermidine and different species of acetylated spermidine for binding to 6xHis-tagged antizyme purified from E. coli.