RL-translated cyclin B protein is not required to induce cyclin A
cleavage. (A) Blocking cyclin B synthesis does not
affect cyclin A cleavage. Cyclin B DNA was mixed with RL either in the
absence or presence of cycloheximide (1 mg/ml). No cyclin B
translation was detected when cycloheximide was added
(Lower). The RL were then incubated with GST-cyclin
A(CΔ114) for the indicated time, and cleavage of cyclin A was
detected by SDS/PAGE and Coomassie blue staining
(Upper). (B) Cyclin A proteolytic
activity is present in the DNA and DN5α lysate. GST-cyclin A(CΔ114)
was incubated with buffer, cyclin B(RL), cyclin B DNA, DH5α lysate,
or BL21(DE3) lysate as indicated. GST-cyclin A(CΔ114) was not added
in the reactions in lanes 6 and 8. Cleavage of cyclin A was detected by
SDS/PAGE and Coomassie blue staining. Molecular size
standards (lane 1) in kDa are indicated on the left.