An altered-specificity mutation in a human POU domain demonstrates functional analogy between the POU-specifc subdomain and phage λ repressor

Agnes Jancso, Martyn C. Botfield, Lawrence C. Sowers, Michael A. Weiss

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

The POU motif, conserved among a family of eukaryotic transcription factors, contains two DNA-binding domains: an N-terminal POU-specific domain (POUS) and a C-terminal homeodomain (POUHD) Surprisingly, POUS is similar in structure to the helix-turn-helix domains of bacteriophage repressor and Cro proteins. Such similarity predicts a common mechanism of DNA recognition. To test this prediction, we have studied the DNA-binding properties of the human Oct-2 POU domain by combined application of chemical synthesis and site-directed mutagenesis. The POUs footprint of DNA contacts, identified by use of modified bases, is analogous to those of bacteriophage represser-operator complexes. Moreover, a loss-of-contact substitution in the putative POU8 recognition α-helix leads to relaxed specificity at one position in the DNA target site. The implied side chain-base contact is identical to that of bacteriophage repressor and Cro proteins. These results establish a functional analogy between the POUs and prokaryotic helix-turn-helix elements and suggest that their DNA specificities may be governed by a shared set of rules.

Original languageEnglish (US)
Pages (from-to)3887-3891
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume91
Issue number9
StatePublished - Apr 26 1994
Externally publishedYes

Keywords

  • DNA-binding proteins
  • DNA-protein interactions
  • Macromolecular recognition
  • Mutagenesis
  • Transcription factors

ASJC Scopus subject areas

  • General

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