Ectopically expressed CBFβ-SMMHC does not inhibit definitive hematopoiesis.

(A) Schematic diagram of the wild-type CBFβ(p22) protein and one of the CBFβ-SMMHC proteins generated by the inv(16). (B) Western blot documenting ectopic expression of the 67-kd CBFβ-SMMHC protein in Cbfb^+/+, Cbfb^+/−, andCbfb^−/−ES cells, and expression of the 71-kd CBFβ-SMMHC protein in cells heterozygous for a “knocked-in”Cbfb^Cbfb-MYH11 allele.41 Open arrow indicates the endogenous CBFβ proteins; closed arrows indicate the ectopically expressed CBFβ-SMMHC proteins. (C) Hematopoietic progenitor development in EBs derived from ES cells expressing the CBFβ-SMMHC protein. The Cbfb genotype of the ES cell is indicated, followed by the protein expressed from the transgene. Colony assays were performed on EBs generated from 10 days of primary culture. The mean values (± SD) of total colony numbers in 3 independent experiments are shown. The differences in colony numbers in cells with or without the transgene were not statistically significant.