Figure 1.Oncogenic
N-RASQ61K induces proliferative arrest and senescence of human
melanocytes.
(A) Human melanocytes were transduced with
lentiviruses expressing N-RASQ61K or copGFP control. The
efficiency of transduction was controlled with the co-expression of copGFP
and was consistently above 90%. Cell proliferation (Ki67), chromatin
condensation (DAPI), and the appearance of increased SA-β-Gal activity were
analyzed and quantitated 15 days after infection. Percentage of cells
positive for the indicated marker is shown in histograms, which correspond
to the mean ± s.d. of at least two independent transduction experiments
from a total of at least 300 cells. Cells enlarged to show DAPI-stained
chromatin foci are indicated with arrows (bar =10 μm). LM, light
microscopy (bar=100μm). (B) Human
epidermal melanocytes infected with lentiviruses expressing N-RASQ61K
or copGFP were stained with DAPI and antibodies to H3K9Me, 15 days post
transduction (bar =10 μm). (C)
Expression of the indicated proteins was determined by western blot
analysis 15 days after infection of human epidermal melanocytes with
lentiviruses expressing N-RASQ61K or copGFP control.
