Requirement of cis-sequence of egr-1 and c-fos promoter for IL-3=n or GM-CSF=ninduced transcriptional activation. (A) Various egr-1 promoter CAT constructs were transfected into BA/FGMR cells and cells were stimulated with either mIL-3 or hGM-CSF. (B) Upper panel: plasmids with various lengths of the c-fos promoter fused to the CAT coding region were transfected into BA/FGMR cells. The CAT activities induced by mIL-3 or hGM-CSF were analyzed by diffusion analysis. Lower panel: CAT activities induced by IL-3/GM-CSF in BA/FGMR cell of the c-fos promoter fragments fused to TK-minimal promoter and CAT coding region were analyzed as described. CAT activities induced by mIL-3 () or hGM-CSF (▨) were analyzed by diffusion analysis. (;bb) CAT value of unstimulated cells (A and B).