Fig. 6. (A) The interaction between Cdc2 and Cdc13 in cdc37-184, cdc37-681 and cdc37⁺ strains was analysed. Strains were cultured at 28 and 36°C over a 4 hour time course and samples of cells were taken as shown. Cdc13 was immunoprecipitated from protein extracts with the anti-Cdc13 6F 10/11 antibody. Western blot analysis was carried out with anti-Cdc13 6F 10/11 and anti-PSTAIR antibodies. (B) The interaction between Cdc2 and Cdc13 in cdc37-184, cdc25-22 and cdc37⁺ strains was analysed. Strains were cultured at 28 and 36°C over a 3 hour time course and samples of cells were taken hourly. Cdc13 was immunoprecipitated from protein extracts with the anti-Cdc13 6F 10/11 antibody. Western blot analysis was carried out with anti-Cdc13 6F 10/11 and anti-PSTAIR antibodies. (C) Immunoprecipitation experiments to detect a biochemical interaction between Cdc2 and Cdc37 in native S. pombe protein extracts from cdc37+, cdc37-681 and cdc37-184 cells cultured at both 28 and 36°C. Immunoprecipitates with the anti-S. pombe Cdc37 and anti-rat IgG (control) antibodies were run on SDS-PAGE and analysed by western blot to determine whether Cdc2 precipitates with Cdc37 from native S. pombe protein extracts.