Evolution of Telomeres in Schizosaccharomyces pombe and Its Possible Relationship to the Diversification of Telomere Binding Proteins.
Telomeres of nuclear chromosomes are usually composed of an array of tandemly repeated sequences that are recognized by specific Myb domain containing DNA-binding proteins (telomere-binding proteins, TBPs). Whereas in many eukaryotes the length and sequence of the telomeric repeat is relatively conserved, telomeric sequences in various yeasts are highly variable. Schizosaccharomyces pombe provides an excellent model for investigation of co-evolution of telomeres and TBPs. First, telomeric repeats of S. pombe differ from the canonical mammalian type TTAGGG sequence. Second, S. pombe telomeres exhibit a high degree of intratelomeric heterogeneity. Third, S. pombe contains all types of known TBPs (Rap1p [a version unable to bind DNA], Tay1p/Teb1p, and Taz1p) that are employed by various yeast species to protect their telomeres. With the aim of reconstructing evolutionary paths leading to a separation of roles between Teb1p and Taz1p, we performed a comparative analysis of the DNA-binding properties of both proteins using combined qualitative and quantitative biochemical approaches. Visualization of DNA-protein complexes by electron microscopy revealed qualitative differences of binding of Teb1p and Taz1p to mammalian type and fission yeast telomeres. Fluorescence anisotropy analysis quantified the binding affinity of Teb1p and Taz1p to three different DNA substrates. Additionally, we carried out electrophoretic mobility shift assays using mammalian type telomeres and native substrates (telomeric repeats, histone-box sequences) as well as their mutated versions. We observed relative DNA sequence binding flexibility of Taz1p and higher binding stringency of Teb1p when both proteins were compared directly to each other. These properties may have driven replacement of Teb1p by Taz1p as the TBP in fission yeast.
Department of Genetics, Comenius University in Bratislava, Faculty of Natural Sciences, Ilkovicova 6, 842 15, Bratislava, Slovak Republic.
Regina
R
Sepsiova
Chromatin Molecular Complexes, Central European Institute of Technology, Masaryk University, Brno, CZ-62500, Czech Republic.|Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, CZ-62500, Czech Republic.
Ivona
I
Necasova
Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599, United States of America.
Smaranda
S
Willcox
Department of Genetics, Comenius University in Bratislava, Faculty of Natural Sciences, Ilkovicova 6, 842 15, Bratislava, Slovak Republic.
Katarina
K
Prochazkova
Department of Genetics, Comenius University in Bratislava, Faculty of Natural Sciences, Ilkovicova 6, 842 15, Bratislava, Slovak Republic.
Peter
P
Gorilak
Department of Biochemistry, Comenius University in Bratislava, Faculty of Natural Sciences, Ilkovicova 6, 842 15, Bratislava, Slovak Republic.
Jozef
J
Nosek
Chromatin Molecular Complexes, Central European Institute of Technology, Masaryk University, Brno, CZ-62500, Czech Republic.|Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, CZ-62500, Czech Republic.
Ctirad
C
Hofr
Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599, United States of America.
Jack D
JD
Griffith
Department of Genetics, Comenius University in Bratislava, Faculty of Natural Sciences, Ilkovicova 6, 842 15, Bratislava, Slovak Republic.
Lubomir
0000-0003-4886-1910
L
Tomaska
D000818:Animals; D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D024202:Electrophoretic Mobility Shift Assay; D019143:Evolution, Molecular; D005454:Fluorescence Polarization; D014644:Genetic Variation; D006801:Humans; D008854:Microscopy, Electron; D009841:Oligonucleotides / Q000235:genetics / Q000378:metabolism; D010802:Phylogeny; D011485:Protein Binding; D012568:Schizosaccharomyces / Q000235:genetics*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure; D016615:Telomere / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure; D034501:Telomere-Binding Proteins / Q000145:classification / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure
D004268:DNA-Binding Proteins; D009841:Oligonucleotides; D029702:Schizosaccharomyces pombe Proteins; C579348:Teb1 protein, S pombe; D034501:Telomere-Binding Proteins; D014157:Transcription Factors; C104344:taz1 protein, S pombe