2 SEPARABLE PROMOTERS CONTROL DIFFERENT ASPECTS OF EXPRESSION OF A DICTYOSTELIUM GENE

A single copy Dictyostelium gene was dissected and elements responsible for its complex pattern of regulation were defined by transcript analysis of gene fusions. Two overlapping promoters responsible for the transcription of an 'L' and an 'S' mRNA could be defined. Further dissection of the P8A7 L promoter resulted in the identification of a sequence necessaryfor stress induction and an element required for vegetative expression. The P8A7 S promoter could be reduced to 449 bp which were sufficient for expression in developing cells. The sequence element required for this transcriptional activity was shown to reside in a51 bp fragmen. Our results show that differential expression of the P8A7 gene is mediated by two independently functioning promoters which, however, share some regulatory elements. A third nuclear RNAspecies 'P' was due to the stress-sensitivity of the 3′ processing signal. © 1990 Oxford University Press.