View the Current Issue

Article

  • The EMBO Journal (2001) 20, 4892 - 4900
  • doi:10.1093/emboj/20.17.4892

NoRC—a novel member of mammalian ISWI-containing chromatin remodeling machines

Ralf Strohner2,4, Attila Nemeth1,4, Petr Jansa3, Urs Hofmann-Rohrer1, Raffaella Santoro1, Gernot Längst2 and Ingrid Grummt1

  1. Division of Molecular Biology of the Cell II, Deutsches Krebsforschungszentrum, D-69120 Heidelberg, Germany
  2. Adolf-Butenandt-Institut, Schillerstras zlige 44, D-80336 München, Germany
  3. Present address: Academy of Sciences of the Czech Republic, Institute of Molecular Genetics, Videnska 1083, 142 20 Praha 4, Czech Republic
  4. Ralf Strohner and Attila Nemeth contributed equally to this work

Correspondence to:

Ingrid Grummt, E-mail: I.Grummt@DKFZ-Heidelberg.de

Received 23 May 2001; Accepted 12 July 2001; Revised 5 July 2001

Transcription by RNA polymerase I on nucleosomal templates requires binding of the transcription termination factor TTF-I to a cognate site 160 bp upstream of the transcription start site. Binding of TTF-I is accompanied by changes in the chromatin architecture which suggests that TTF-I recruits a remodeling activity to the rDNA promoter. We have cloned a cDNA that encodes TIP5 (TTF-I-interacting protein 5), a 205 kDa protein that shares a number of important protein domains with WSTF (Williams syndrome transcription factor) and hAcf1/WCRF180, the largest subunits of human chromatin remodeling complexes hCHRAC and WCRF. TIP5 co-localizes with the basal RNA polymerase I transcription factor UBF in the nucleolus and is associated with SNF2h. The cellular TIP5–SNF2h complex, termed NoRC (nucleolar remodeling complex), induces nucleosome sliding in an ATP- and histone H4 tail-dependent fashion. The results suggest that NoRC is a novel nucleolar chromatin remodeling machine that may serve a role in the regulation of the rDNA locus.

  • Keywords:

    • Acf1,
    • chromatin remodeling,
    • RNA polymerase I,
    • SNF2h,
    • TTF-I