FIGURE 6.

Cyclin D1·CDK4 can reverse the cell cycle arrest induced by INSM1. A, Cos-7 cells ectopically expressing INSM1 were synchronized by serum starvation and then stimulated by adding 10% serum for 24 h. Ad-LacZ or Ad-cyclin D1·CDK4 was added during the serum stimulation. Cell cycle progression was measured by propidium iodide (PI) staining using flow cytometric analysis. Overexpression of cyclin D1·CDK4 could reverse the cell cycle arrest caused by INSM1. B, co-immunoprecipitation (IP) of cyclin D1 revealed that overexpression of cyclin D1 and CDK4 can restore the cyclin D1·CDK4 complex even in the presence of INSM1. C, percentage of cell cycle distribution. WB, Western blot.