Figure 7.

Cdh1 activates Xenopus interphase extracts to degrade itself. (A) Xenopus interphase extracts were used for a destruction assay of [³⁵S]methionine-labeled S. pombe cyclin B (cdc13) and its destruction box deletion cdc13Δ67, which served as a loading control and control for nonspecific degradation. Extracts were supplemented with Cdh1, Cdh1-R and Cdh1DM as indicated. Aliquots were collected at the indicated times (in hours), and resolved by SDS–PAGE. (B) [³⁵S]methionine-labeled Cdh1, Cdh1-R and Cdh1DM were added to Xenopus interphase extracts and analyzed like in (A). (C) Xenopus interphase extracts pre-activated with Cdh1 mRNA were used for a destruction assay of [³⁵S]methionine-labeled S. pombe cyclin B (cdc13), cdc13Δ67, wild-type and mutant Cdh1 and human securin.