Figure 1. Decreased deneddylation activity in CSN8^neoflox/− (CSN8^hypo) mouse hearts.

Age-matched littermate CSN8^neoflox/+ mice were used as controls (CTL). (A) Csn8-targeted alleles described in this study. The numbered light grey rectangles denote the exons. In the neoflox allele (CSN8^neoflox), a neomycin phosphotransferase II gene (NEO) flanked by Frt sites (empty triangles) are inserted between exon 3 and 4; and exons 4 through 6 are flanked by LoxP sites (solid triangles). In CSN8 knockout allele (CSN8⁻), the NEO cassette and exons 4 through 6 are deleted by FLP- and Cre- mediated recombination. (B, C) Western blot analyses of indicated proteins. Representative images (B) and pooled densitometry data (C) are shown. GAPDH serves as a loading control. (D, E) Representative images (D) and pooled densitometry data (E) from western blot analyses of indicated cullin proteins in mouse hearts. Arrows mark the neddylated form of cullins. (F, G) Representative images (F) and pooled densitometry data (G) from western blot analyses of neddylated proteins in mouse hearts. Total neddylated proteins (revealed by long-time exposure) and neddylated cullin (revealed by short-time exposure) are increased in CSN8^hypo hearts. N=3 mice/group; *p<0.05, #p<0.01 vs. CTL; t-test.