Figure 4.

Rac requirement for growth factor-independent colony formation of BCR/ABL-expressing mouse marrow cells. (Upper) Detection of BCR/ABL and mutant Rac mRNA transcripts in mouse bone marrow cells infected with BCR/ABL- and/or Rac-coding retroviruses. β-actin was detected as positive control for RNA loading and integrity. (Lower) Methylcellulose colony formation of mouse bone marrow cells infected with BCR/ABL- and/or Rac-coding retroviruses and cultured in the absence or in the presence of threshold concentrations (0.1 unit/ml) of recombinant murine IL-3. Results represent two independent experiments and are expressed as mean ± SD.