Structure and Activation of the Human N-Ras Gene

The normal human N-ras gene was cloned. In structure and sequence it closely resembles the human H-ras and K-ras genes. The 3 genes share regions of nucleotide homology and nucleotide divergence within coding sequences and have a common intron/exon structure, indicating that they evolved from a similarly spliced ancestral gene. The N-ras gene of SK-N-SH neuroblastoma cells has transforming activity, while the normal N-ras gene does not, the result of a single nucleotide change substituting Lys for Gln in position 61 of the N-ras gene product. Amino acid substitutions in 2 distinct regions can activate the transforming potential of ras gene products