Fission yeast contains an rDNA binding activity that interacts specifically with regulatory sequences for ribosomal RNA synthesis

Basal level transcriptional initiation of fission yeast ribosomal RNA genes is dependent on the con ribosomal RNA gene promoter and is stimulated by a n upstream rDNA promoter element and by regulatory sequences located in its similar to 3.5 kb intergenic rDNA spacer. A Schizosaccharomyces pombe sequ ence-specific rDNA binding activity was characterized that interacted with the upstream rDNA promoter region and that associated with required RNA pol ymerase I transcription components in initial fractionation steps. The rDNA binding activity was further purified and found to specifically associate with a region of the rDNA promoter between -80 and -56, The promoter region required for stable binding correlates with that mediating activated level s of transcriptional initiation. This rDNA binding activity stimulates in v itro rRNA synthesis supported by templates bearing this upstream promoter d omain but not by templates lacking it. (C) 2000 Elsevier Science B.V. All r ights reserved.