Morphology and cell surface phenotype of cell lines derived from secondary cultures of Cbfb^Cbfb-MYH11/+ES cells.

(A) Growth curve showing expansion of cells derived from secondary cultures of wild-type (WT, ●) andCbfb^Cbfb-MYH11/+ ES cells (KI-1, ■, and KI-2, ⋄). (B) Giemsa stains of cells derived from secondary cultures ofCbfb^+/+ andCbfb^Cbfb-MYH11/+ ES cells (KI-1, KI-2). Cytocentrifuge preparations of the Cbfb^+/+ and KI-1 cells were made after 42 days in liquid culture. KI-2 preparations were made after 85 days in liquid culture. (C) Western blot analysis documenting continued expression of the CBFβ-SMMHC protein in the KI-1 and KI-2 cell lines. Lanes: 1, +/+ ES cells; 2,Cbfb^Cbfb-MYH11/+ ES cells; 3, KI-1 cells; 4, KI-2 cells. Molecular weight markers are indicated on the right. (D) Flow cytometric analysis of surface antigen expression on KI-1 cells expanded in liquid culture. Heavy black line represents staining obtained with antibodies specific for the indicated hematopoietic antigen. Lighter line corresponds to the signal obtained with a control antibody. Number in upper right hand corner indicates percentage of cells positive for surface expression of each marker. (E) Flow cytometric analysis of surface antigen expression on KI-2 cells.