Human rRNA Transcription Is Modulated by the Coordinate Binding of Two Factors to an Upstream Control Element

Cell. 1986 Jun 20;45(6):847-57. doi: 10.1016/0092-8674(86)90559-3.

Abstract

The human rRNA promoter contains two distinct cis-control sequences, the core and upstream control element (UCE), that serve as the target for binding cellular trans-activating proteins involved in transcription initiation by RNA polymerase I. One of these factors, SL1, has been extensively purified and shown to be a species-specific factor required to reconstitute in vitro RNA synthesis. DNAase footprinting revealed that although SL1 alone does not bind specifically to rRNA promoter sequences, a second factor, UBF1, recruits SL1 to the template and directs binding to an extended region encompassing sequences in the UCE. Analysis of mutant and human-mouse hybrid promoters indicate that protein-DNA interactions at the UCE modulate the efficiency of rRNA synthesis. Transcription from the human rRNA promoter appears to require an unusual set of protein-DNA transactions in which recognition and binding to an upstream cis-control element is carried out by one factor (UBF1), whereas activation requires an additional factor, SL1, acting in conjunction with UBF1 to trigger transcription.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Binding Sites
  • DNA / genetics
  • DNA / metabolism*
  • HeLa Cells
  • Humans
  • Mice
  • Mutation
  • Promoter Regions, Genetic*
  • RNA Polymerase I / metabolism
  • RNA, Ribosomal / biosynthesis
  • RNA, Ribosomal / genetics*
  • Species Specificity
  • Transcription Factors / metabolism*
  • Transcription, Genetic*

Substances

  • RNA, Ribosomal
  • Transcription Factors
  • DNA
  • RNA Polymerase I