DIF-1 regulates Dictyostelium basal disc differentiation by inducing the nuclear accumulation of a bZIP transcription factor

► The DimB transcription factor is nuclear enriched only in pstB cells of the slug. ► A dimB null lacks pstB cells and derivative tissues: the lower cup and basal disc. ► DIF induces DimB to bind to the ecmB promoter, a marker of pstB differentiation. ► DIF is the direct inducer of ecmB gene expression and pstB cell differentiation.