HeLa cells were co-transfected with 1 ug of mFli1 −271/−37 P/R vector and either 100 ng of an empty expression vector (pcDNA3) or increasing amounts of Ets1, Ets2, PU.1, Fli1, Elf1 or Tel (A) expression vectors. (B) HeLa cells were co-transfected with 1.0 ug of Fli1 −271/−37 P/R vector and either 100 ng of Ets1, Ets2, Fli1 or Elf1 along with an increasing amount of Tel expression vector. (C) HeLa cells were co-transfected with various Ets factors and either the Fli1 −271/−37 P/R alone or the P/R containing mutations in 3 of the 4 Ets binding sites indicated. (A and C) Expression is presented relative to the P/R vector co-transfected with the empty expression vector pcDNA3, which was set to 1. (B) Expression is presented relative to the P/R vector co-transfected with Ets1, Ets2, Fli1 or Elf1, which was set to 1. Results are representative of at least three separate transfections. Students T test was used to compare relative expression to mFli1 −271/−37 P/R plus pcDNA3 (A) or mFli1 −271/−37 P/R plus Ets1, Ets2, Fli1 or Elf1 (B). P-values < 0.05 considered significant as indicated by (*).