Mechanism of activation of an N-ras gene in the human fibrosarcoma cell line HT1080.

Abstract

A full length N‐ras gene has been cloned from both the human fibrosarcoma cell line HT1080 and from normal human DNA. N‐ras isolated from HT1080 will efficiently induce morphological transformation of NIH/3T3 cells in a transfection assay, whereas N‐ras isolated from normal human DNA has no effect on NIH/3T3 cells. The coding regions of the normal N‐ras gene have been sequenced and the predicted amino acid sequence of the N‐ras product is very similar to that of the c‐Ha‐ras1 and c‐Ki‐ras2 products. By making chimeric molecules between the two cloned genes the activating alteration in the HT1080 N‐ras gene has been localised to a single base change that results in an amino acid alteration at position 61 of the p21 N‐ras product.