RNA polymerase 1 promoter selectivity factor SL1

Function

• SL1 is responsible for species specificity of rRNA transcription

Structure

• 4 subunits
  • TBP
    • since the promoter for ribosomal RNA genes does not contain a TATA box, TBP does not bind to specific promoter sequences
    • instead, the association of TBP with ribosomal RNA genes is mediated by the binding of other proteins in the SL1 complex to the promoter, a situation similar to the association of TBP with the Inr sequences of polymerase 2 genes that lack TATA boxes

More general terms

• transcription factor (TF)
• DNA-binding protein
• molecular complex