Induction of transcription of egr-1 by mIL-3 or hGM-CSF in BA/FGMR cells. (A) Induction of egr-1 mRNA was analyzed by Northern blot analysis. Total RNA of BA/FGMR cells stimulated by either mIL-3 or hGM-CSF at the indicated time was subjected to Northern blot analysis using egr-1 cDNA fragment as a probe. (B) Plasmid-containing egr-1 promoter fragment (nts ;k2606 to ;k18) fused to CAT coding region was transfected to BA/FGMR cells, and CAT activities induced by either mIL-3, hGM-CSF, or mIL-4 were analyzed by diffusion analysis, as described in the Materials and Methods.