Bmx induces Stat-mediated transcription. (A) COS cells were transfected with Stat1α expression vector together with a luciferase reporter vector containing a wild-type (wt) or a mutant GAS-site (mut-GAS). In addition, cells were transfected with Jak2 or Bmx expression vectors. In control lysates cells were transfected with wild-type GAS luciferase construct alone or together with Stat1 expression vector. Cell lysates were analyzed for Stat1-dependent luciferase activity normalized to constitutively expressed luciferase activity from a cotransfected control vector (see Materials and Methods for details). The values shown are means from three independent experiments and standard errors of the mean. (B) COS cells were transfected with a luciferase reporter containing a Stat5 binding site from the promoter region of the Spi gene. Additionally the cells were transfected with Bmx-HA, Jak2-HA, or Jak1 expression vectors or with an empty vector as a control. Cell lysates were analyzed for Stat5-dependent luciferase activity as in (A).