TRANSCRIPTIONAL ACTIVATION OF A RAS-LIKE GENE (KIR) BY ONCOGENIC TYROSINE KINASES

We report the characterization of a member of the ras gene family that is overexpressed in cells transformed by abl tyrosine kinase oncogene s. The gene, named kir (for kinase-inducible ras-like), is induced at the transcriptional level, kit mRNA has a rapid turnover and encodes a protein of 33 kDa with guanine nucleotide-binding activity but undete ctable intrinsic GTPase activity. kir was cloned by differential scree ning of genes present in fully malignant versus growth factor-independ ent cell lines expressing wild-type or mutant forms of BCR/ABL, BCR/AB L and v-Abl induce transcription of the kir gene via specific signalin g pathway(s), but kir overexpression alone is not sufficient to mediat e transformation.