Trib1 and Trib2, but not Trib3, confer serial plating activity in methylcellulose cultures. (A) Serial colony assays were performed as shown using primary BM cells transduced with retroviruses. (B) Primary methylcellulose cultures were sorted for GFP and used for RNA isolation. Absolute quantification of Trib1, Trib2, or Trib3 mRNA normalized to EF1α from sorted BM cells after 8 days of culture in methylcellulose. Values are mean (± SD) for triplicate samples. Data are representative of 2 independent experiments. (C) The colony numbers were counted during 3 rounds of serial culture and normalized to starting GFP. Values are mean (± SD) for triplicate samples. NC indicates no colonies. Data are representative of 3 independent experiments. (D) Plates from the third serial culture are shown.