Altered DNA-binding specificity mutants of EKLF and Sp1 show that EKLF is an activator of the β-globin locus control region in vivo

  1. Nynke Gillemans,
  2. Rita Tewari,
  3. Fokke Lindeboom,
  4. Robbert Rottier,
  5. Ton de Wit,
  6. Mark Wijgerde,
  7. Frank Grosveld1, and
  8. Sjaak Philipsen
  1. Erasmus University Rotterdam, Medical Genetics Center–Department of Cell Biology, 3000 DR Rotterdam, The Netherlands

Abstract

The locus control region of the β-globincluster contains five DNase I hypersensitive sites (5′HS1–5) required for locus activation. 5′HS3 contains six G-rich motifs that are essential for its activity. Members of a protein family, characterized by three zinc fingers highly homologous to those found in transcription factor Sp1, interact with these motifs. Because point mutagenesis cannot distinguish between family members, it is not known which protein activates 5′HS3. We show that the function of such closely related proteins can be distinguished in vivo by matching point mutations in 5′HS3 with amino acid changes in the zinc fingers of Sp1 and EKLF. Testing their activity in transgenic mice shows that EKLF is a direct activator of 5′HS3.

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Footnotes

  • 1 Corresponding author.

  • E-MAIL vangeest{at}ch1.fgg.eur.nl; FAX 31-10-436 0225.

    • Received June 5, 1998.
    • Accepted July 29, 1998.
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