Fig. 3. Immunoblot analysis of sumoylation. The genotypes are shown above the lanes; wt, wild type; hmz, homozygous; het, heterozygous. Molecular mass in kilodaltons (kDa) is shown to the left of each panel. (A) Whole-embryo extracts immunoblotted with anti-SUMO1 antibody. There is complete lack of high molecular mass SUMO1 conjugates (upper panel) and free SUMO1 (lower panel) in homozygotes, and reduced levels in heterozygotes. (B) Same blot as in upper panel of A, reanalyzed with anti-RanGAP1 antibody. Sumoylated form of RanGAP1 is present even in homozygotes. (C) Whole-embryo extracts immunoblotted with anti-SUMO3 antibody. Band at the position of sumoylated RanGAP1 (>75 kDa) is more intense in homozygotes. Higher molecular mass SUMO2/3 conjugates are essentially unchanged.