“…In contrast, the pKBE-2 probe, containing the v-Ki-ras gene [24], detected EcoRI fragments of 6.7, 3.0-3.1 and 2.5 kbp, in addition to the endogenous mouse c-Ki-ra.s fragments, in the DNA of two primary transformants ( fig.lB, lanes 1 and 4,5, [27]. Fig.2 (lanes b,c) shows that both transformants expressed clearly detectable amounts of p21 protein, although at a slightly lower level than that expressed by the PCC4 mouse teratocarcinoma cell line used as a positive control (lane a) and in which the c-Ki-ras gene is amplified at least IO-fold [18]. Comparatively, the p21 ras protein band was barely detectable in lysates from untransformed NIH 3T3 cells (not shown).…”