sentence: As shown in Fig. 7c , in control reactions lacking the proteasome-specific inhibitor , MG-132 , CYCA1 ; 1 , CYCB1 ;3 , and CYCD2 ; 1 were progressively degraded by 7-DAP endosperm extracts ( panels labeled with a minus symbol ) , although CYCD5 ; 1 was relatively more stable .