title: Structure of the Ki-ras gene of the human lung carcinoma cell line Calu-1.
abstract: The homologue of the viral Kirsten ras (v-Ki-ras) gene found in the human lung carcinoma cell line, Calu-1, has an intron-exon structure similar to that of the human homologue of the viral Harvey ras (v-Ha-ras) gene. A second, potential fourth coding exon is present in the human Ki-ras gene and similar sequences are found in the Kirsten murine sarcoma virus. Cysteine is encoded at the twelfth amino acid position, suggesting that the Calu-1 Ki-ras gene has undergone a mutational activation at the same position as the human Ha-ras gene of the bladder carcinoma cell line, T24. A comparison of their predicted amino acid sequences suggests that ras proteins have a 'constant' region and a 'variable' region. Here we propose a common modular structure for ras gene products in which the variable region forms a physiologically important combining site.
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002277:Carcinoma / Q000235:genetics*; D002460:Cell Line; D002472:Cell Transformation, Viral; D005814:Genes, Viral; D006801:Humans; D007708:Kirsten murine sarcoma virus / Q000235:genetics*; D008175:Lung Neoplasms / Q000235:genetics*; D009857:Oncogenes; D009053:Sarcoma Viruses, Murine / Q000235:genetics*; D014764:Viral Proteins / Q000235:genetics
chemical_list: D014764:Viral Proteins