Functional analysis of the promoter of the gene encoding the acidic ribosomal protein L45 in yeast.

The gene encoding the acidic ribosomal protein L45 in yeast is expressed coordinately with other rp-genes. The promoter region of this gene harbours binding sites for CP1 and ABF1. We demonstrate that the CP1-site is not involved in the transcription activation of the L45-gene. Rather, the ABF1-site, through deviating from the consensus sequence (RTARY3N3ACG), appears to be essential for efficient transcription. Replacement of this site by a consensus RAP1-binding site (an RPG box) did not alter the transcriptional yield of the L45-gene. An additional transcription activating region is present downstream of the ABF1-site. The relevant nucleotide sequence, which is repeated in the L45-gene promoter, gives rise to complex formation with a yeast protein extract in a bandshift assay. The results indicate that the L45-gene promoter has a complex architecture.