Cell
Volume 67, Issue 4, 15 November 1991, Pages 807-814
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Cloning and expression of genes for the Oxytricha telomere-binding protein: Specific subunit interactions in the telomeric complex

https://doi.org/10.1016/0092-8674(91)90075-AGet rights and content

Abstract

Telomeres of Oxytricha nova macronuclear chromosomes consist of a repeated T4G4 sequence, single-stranded at the 3′ terminus, bound by a heterodimeric protein. The cloning of genes for the two polypeptides and their separate expression in E. coli have enabled evaluation of their individual contributions to DNA binding. The 56 kd α subunit binds single-stranded DNA by itself, one polypeptide per T4G4 block; multiple subunits can coat a (T4G4)n multimer. The derived amino acid sequence of α does not reveal any known DNA-binding motif, so it appears to represent a novel type of DNA-binding protein. The previously cloned 41 kd β subunit does not by itself protect DNA from methylation, but is required along with α to recreate the pattern of methylation protection indicative of telomeres in vivo. The unusual ability of the protein to engage in two different interactions with the same telomeric DNA sequence might provide the versatility necessary for diverse telomere functions.

References (47)

  • M.K. Raghuraman et al.

    Assembly and self-association of Oxytricha telomeric nucleoprotein complexes

    Cell

    (1989)
  • C.H. Squires et al.

    Production and characterization of human fibroblast growth factor from Escherichia coll

    J. Biol. Chem.

    (1988)
  • F.W. Studier et al.

    Use of bacteriophage T7 RNA polymerase to direct selective high-level expression of cloned genes

    J. Mol. Biol.

    (1986)
  • J.R. Williamson et al.

    Monovalent cation-induced structure of telomeric DNA: the G-quartet model

    Cell

    (1989)
  • D.A. Agard et al.

    Three-dimensional architecture of a polytene nucleus

    Nature

    (1983)
  • E.H. Blackburn

    Structure and function of telomeres

    Nature

    (1991)
  • A.R. Buchman et al.

    Two DNA-binding factors recognize specific sequences at silencers, upstream activation sequences, autonomous replication sequences, and telomeres in Saccharomyces cerevisiae

    Mol. Cell. Biol.

    (1988)
  • J.S. Coren et al.

    Characterization of a telomere-binding protein from Physarum polycephalum

    Mol. Cell. Biol.

    (1991)
  • I.B. Dodd et al.

    Improved detection of helix-turn-helix DNA binding motifs in protein sequences

    Nucl. Acids Res.

    (1990)
  • S.P. Eisenberg et al.

    Primary structure and functional expression from complementary DNA of a human interleukin-1 receptor antagonist

    Nature

    (1990)
  • A.F. Greslin et al.

    Reordering of nine exons is necessary to form a functional actin gene

  • N. Hanyu et al.

    Dramatic events in ciliate evolution: alteration of UAA and UAG termination codons to glutamine codons due to anticodon mutations in two Tetrahymena tRNAsGln

    EMBO J.

    (1986)
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    Present address: Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588.

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