Activated levels of rRNA synthesis in fission yeast are driven by an intergenic rDNA region positioned over 2500 nucleotides upstream of the initiation site.
RNA polymerase I-catalyzed synthesis of the Schizosaccharomyces pombe approximately 37S pre-rRNAs was shown to be sensitive to regulatory sequences located several kilobases upstream of the initiation site for the rRNA gene. An in vitro transcription system for RNA polymerase I-catalyzed RNA synthesis was established that supports correct and activated transcription from templates bearing a full S. pombe rRNA gene promoter. A 780 bp region starting at -2560 significantly stimulates transcription of ac is-located rDNA promoter and competes with an rDNA promoter in trans, thus displaying some of the activities of rDNA transcriptional enhancers in vitro. Deletion of a 30 bp enhancer-homologous domain in this 780 bp far upstream region blocked its cis-stimulatory effect. The sequence of the S. pombe 3.5 kb intergenic spacer was determined and its organization differs from that of vertebrate, Drosophila, Acanthamoeba and plant intergenic rDNA spacers: it does not contain multiple, imperfect copies of the rRNA gene promoter nor repetitive elements of 140 bp, as are found in vertebrate rDNA enhancers.
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Department of Chemistry, New York University, New York, NY 10003, USA.
Zhao
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Chen
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D000818:Animals; D001483:Base Sequence; D004271:DNA, Fungal; D004275:DNA, Ribosomal; D004742:Enhancer Elements, Genetic; D008969:Molecular Sequence Data; D009711:Nucleotides; D010442:Peptide Chain Initiation, Translational; D011401:Promoter Regions, Genetic; D012331:RNA, Fungal / Q000096:biosynthesis*; D012335:RNA, Ribosomal / Q000096:biosynthesis*; D012045:Regulatory Sequences, Nucleic Acid; D012568:Schizosaccharomyces / Q000235:genetics*; D014158:Transcription, Genetic
D004271:DNA, Fungal; D004275:DNA, Ribosomal; D009711:Nucleotides; D012331:RNA, Fungal; D012335:RNA, Ribosomal