Taz1p and Teb1p, two telobox proteins in Schizosaccharomyces pombe, recognize different telomere-related DNA sequences.
Band shift assays were used to study proteins from the fission yeast that bind double-stranded telomeric repeat sequences. We also examine general DNA binding properties of the telobox domain, which characterizes telomere-binding proteins from a range of species. We demonstrate that Taz1p has a high affinity for the fission yeast telomeric repeat, consistent with genetic results implicating this protein in telomere maintenance. A second Schizosaccharomyces pombe telobox protein, Teb1p, is shown to bind with high affinity to the vertebrate repeat and with low affinity to the fission yeast telomeric DNA. When tested on G-rich single-stranded telomeric DNA, all these proteins bind with very low affinity, much like the human telomere-binding protein TRF1. Recombinant proteins containing just the telobox domains reproduce the specificity of binding demonstrated for the corresponding full-length proteins, indicating that the telobox domain is indeed responsible for specific DNA recognition. The presence of possible Teb1p-binding sites upstream of many genes suggests a role for this protein as a general transcription factor. Finally, band shift experiments with whole cell extracts from wild-type and taz1 (-)strains suggest that in addition to Taz1p, S.pombe has another major telomere-binding activity.
Vassetzky
N S
NS
Engelhardt Institute of Molecular Biology, 32 Vavilov Street, Moscow, 117984 Russia,
Gaden
F
F
Brun
C
C
Gasser
S M
SM
Gilson
E
E
D001483:Base Sequence; D001665:Binding Sites; D017931:DNA Primers; D015342:DNA Probes; D004271:DNA, Fungal / Q000737:chemistry* / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000378:metabolism; D005800:Genes, Fungal; D006801:Humans; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000378:metabolism; D012091:Repetitive Sequences, Nucleic Acid; D012568:Schizosaccharomyces / Q000235:genetics* / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins; D016615:Telomere / Q000235:genetics*; D034501:Telomere-Binding Proteins; D035321:Telomeric Repeat Binding Protein 1; D014157:Transcription Factors
D017931:DNA Primers; D015342:DNA Probes; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D011994:Recombinant Proteins; D029702:Schizosaccharomyces pombe Proteins; D034501:Telomere-Binding Proteins; D035321:Telomeric Repeat Binding Protein 1; D014157:Transcription Factors; C512907:reb1 protein, S pombe; C104344:taz1 protein, S pombe