Sequence-specific binding of Taz1p dimers to fission yeast telomeric DNA.
The fission yeast (Schizosaccharomyces pombe) taz1 gene encodes a telomere-associated protein. It contains a single copy of a Myb-like motif termed the telobox that is also found in the human telomere binding proteins TRF1 and TRF2, and Tbf1p, a protein that binds to sequences found within the sub-telomeric regions of budding yeast (Saccharomyces cerevisiae) chromosomes. Taz1p was synthesised in vitro and shown to bind to a fission yeast telomeric DNA fragment in a sequence specific manner that required the telobox motif. Like the mammalian TRF proteins, Taz1p bound to DNA as a preformed homodimer. The isolated Myb-like domain was also capable of sequence specific DNA binding, although with less specificity than the full-length dimer. Surprisingly, a protein extract produced from a taz1- fission yeast strain still contained the major telomere binding activity (complex I) we have characterised previously, suggesting that there could be other abundant telomere binding proteins in fission yeast. One candidate, SpX, was also synthesised in vitro, but despite the presence of two telobox domains, no sequence specific binding to telomeric DNA was detected.
Spink
K G
KG
Institute of Genetics, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK.
Evans
R J
RJ
Chambers
A
A
D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers; D004271:DNA, Fungal / Q000378:metabolism*; D019281:Dimerization; D029968:Escherichia coli Proteins; D006801:Humans; D008969:Molecular Sequence Data; D010749:Phosphoprotein Phosphatases; D011485:Protein Binding; D011494:Protein Kinases; D020598:Proto-Oncogene Proteins c-myb / Q000378:metabolism; D012568:Schizosaccharomyces / Q000235:genetics*; D029702:Schizosaccharomyces pombe Proteins; D017386:Sequence Homology, Amino Acid; D016615:Telomere; D034501:Telomere-Binding Proteins; D020798:Two-Hybrid System Techniques
D001425:Bacterial Outer Membrane Proteins; D017931:DNA Primers; D004271:DNA, Fungal; D029968:Escherichia coli Proteins; D020598:Proto-Oncogene Proteins c-myb; D029702:Schizosaccharomyces pombe Proteins; C072091:Taz1 protein, E coli; D034501:Telomere-Binding Proteins; C104344:taz1 protein, S pombe; D011494:Protein Kinases; D010749:Phosphoprotein Phosphatases