Molecular cloning andthetotal nucleotide sequence ofthe humanc-Ha-ras-1 geneactivated inamelanoma froma Japanese patient

ABSTRACT Thetransforminggeneofmalignantmelano- ma tissue obtainedfromaJapanesepatientandmaintainedinnudemice has been cloned in its biologically active formandidentified asthec-Ha-ras-1 gene, ahomologueofthe viral Ha-rasgene. Nucleotidesequenceanalysisrevealedthatthegenet-ic alteration responsible for the transforming activity of themelanomaoncogenewaslocalized toasinglepointmutationinthe second exon. The transversion ofadenine to thymine re-sults in thesubstitution ofleucineforglutamineasaminoacidresidue 61 ofthe predicted p21 protein. Other nucleotide se-quences spanning a 2.9-kilobase segment including the entireexonsandintronswerefoundtobeexactlythesameasthoseinaproto-oncogenefromanormal Caucasian reported previous- ly, exceptforbasealterationsexplainedas polymorphic differ-ences.The DNA-mediated gene transfer technique (1, 2) has re- vealed a class ofdominant cellular transforming genes acti-vatedin human and rodenttumors. DNAs fromthese tumors have been found to induce morphological transformation of