Essential region for transforming activity of human c-Ha-ras-1.

An SstI fragment of 2.9 kb carrying all four coding exons of the human melanoma c-Ha-ras-1 oncogene could not transform mouse NIH 3T3 cells. Preparation of plasmid clones carrying the 2.9 kb SstI DNA and adjacent regions and analyses of the biological activities of the clones revealed that, for transforming activity of c-Ha-ras-1, a nucleotide sequence of 0.85 kb adjacent to the 2.9 kb DNA in the upstream region was required.