Ba/F3 transformation, by ZNF198–FGFR1, requires ZNF198 proline-rich region but not ZNF198 zinc fingers.

Ba/F3 cells were infected with various ZNF198–FGFR1 retroviral constructs. After G418 selection, the cells were cultured without IL-3, and viable cells were counted daily for 10 days. (A) Ba/F3 cells expressing an N-terminal truncated ZNF198–FGFR1 lacking all zinc fingers, but containing the ZNF198 proline-rich region (ΔZF/MSCV), proliferate as well in the absence of IL-3 as Ba/F3 expressing full-length ZNF198–FGFR1 isoforms (4ZF/MSCV and 10ZF/MSCV). Controls included Ba/F3 cells infected with empty vector and cultured in medium with or without IL-3, and uninfected Ba/F3 cells cultured without IL-3. (B) Ba/F3 cells expressing 4 and 10 zinc finger ZNF198–FGFR1 lacking the proline-rich region (4ZFΔPR/MSCV and 10ZFΔPR/MSCV) do not proliferate in the absence of IL-3. Controls are as in A.