Fig. 7.

Psmb9 is necessary for the accelerated cyclin turnover in Tsc1-cko RPC. a Cell cycle progression of RPCs in E14.5 mouse retinas with combinatorial Tsc1-cko and Psmb9-ko alleles was examined as described in Fig. 2f. Scale bar, 100 μm. b Average percentage of cells expressing each marker in the retinas was provided in a graph (representative images are shown in Supplementary Fig. 12a). c Ratio of BrdU-co-expressing cells to total marker-expressing cells in (a) was also shown in a graph. Numbers of mice used for b and c are 4 (Tsc1-cko;Psmb9-ko) or 5 (the rest genotypes) and from 4 independent litters; error bars denote SD. d Retinal cell lysates (20 μg proteins/lane) obtained from E14.5 littermate mouse embryos were analyzed by WB with corresponding antibodies. e Image pixels of WB bands in each retinal sample were calculated by ImageJ software and relative intensities were obtained by comparing the pixel numbers with those of Psmb9-het;Tsc1-het samples. Values are average measurements of 3 independent WB results. Error bars denote SD. f Activities of the purified proteasomes were analyzed as described in Fig. 6a. The values are averages and error bars denote SD (n = 4; 2 independent litters). g Synthesis and degradation of CcnB1 in the mouse retinas were analyzed by [³⁵S]-Met pulse labeling and chasing experiments explained in Fig. 5e. Relative radioactivities of [³⁵S]-labeled CcnB1 (h) and CcnE1 (i) bands in the retinal explants were obtained by comparing corresponding bands at 0 h. The values are average obtained from 3 independent experiments. Error bars denote SD. P-values are obtained by one-way ANOVA test and shown in the graphs (*<0.05; **<0.01; ***<0.001)