Further Characterization of CDC25 Mm , a Mammalian Activator of p21ras

By using a cotransfection assay with a ras-responsive fos-luciferase reporter gene, we present evidence that the catalytic domain of CDC25Mm constitutively activates p21ras in mammalian cells in vivo. Using immunopurified CDC25Mm-specific antibodies we show that different protein species are recognized in mouse tissues.