Enhancers for RNA polymerase I in mouse ribosomal DNA

Craig S. Pikaard, Louise K. Pape, Sheryl L. Henderson, Kenneth Ryan, Mark H. Paalman, Margaret A. Lopata, Ronald H. Reeder, Barbara Sollner-Webb

Research output: Contribution to journalArticlepeer-review

69 Scopus citations


The intergenic spacer of the mouse ribosomal genes contains repetitive 140-base-pair (bp) elements which we show are enhancers for RNA polymerase I transcription analogous to the 60/81-bp repetitive enhancers (enhancers containing a 60-bp and an 81-bp element) previously characterized from Xenopus laevis. In rodent cell transfection assays, the 140-bp repeats stimulated an adjacent mouse polymerase I promoter when located in cis and competed with it when located in trans. Remarkably, in frog oocyte injection assays, the 140-bp repeats enhanced a frog ribosomal gene promoter as strongly as did the homologous 60/81-bp repeats. Mouse 140-bp repeats also competed against frog promoters in trans. The 140-bp repeats bound UBF, a DNA-binding protein we have purified from mouse extracts that is the mouse homolog of polymerase I transcription factors previously isolated from frogs and humans. The DNA-binding properties of DBF are conserved from the mouse to the frog. The same regulatory elements (terminators, gene and spacer promoters, and enhancers) have now been identified in both a mammalian and an amphibian spacer, and they are found in the same relative order. Therefore, this arrangement of elements probably is widespread in nature and has important functional consequences.

Original languageEnglish (US)
Pages (from-to)4816-4825
Number of pages10
JournalMolecular and cellular biology
Issue number9
StatePublished - Sep 1990

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology


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