High impact information on TBF1

• Because poly(C.A)/poly(T.G) sequences from a wide range of organisms will serve as the primer for the in vivo extension of telomeres in yeast, TBF alpha is of particular interest [1].
• A possible function for TBF alpha might be to serve as an anchoring protein for the yeast telomerase by binding to the conserved junction sequence at a distance from the terminus to allow addition of an irregular repeating sequence at the chromosome end [1].
• The Tbf1 and Reb1 proteins are present in yeast subtelomeric regions [2].
• The DNA sequence of TBF1 was determined [3].
• Diploid cells heterozygous for a tbf1::URA3 insertion mutation are viable but upon sporulation give rise to tetrads with only two viable spores, both of which are Ura-, indicating that the TBF1 gene is essential for growth [3].

Biological context of TBF1

• The yeast TBF1 gene is essential for mitotic growth and encodes a protein that binds the human telomere repeats in vitro, although its cellular function is unknown [4].
• We propose to call the particular Myb-related motif found in these proteins the 'telobox'. Antibodies directed against the Tbf1 telobox detect two proteins in nuclear and mitotic chromosome extracts from human cell lines [5].
• Identification of high affinity Tbf1p-binding sites within the budding yeast genome [4].
• PCR-assisted binding site selection was used to define a consensus for high affinity Tbf1p-binding sites [4].
• Immunofluorescence of Tbf1p shows a spotty pattern throughout the interphase nucleus and along synapsed chromosomes in meiosis, suggesting that Tbf1p binds internal chromosomal sites in addition to sub-telomeric regions [4].

Associations of TBF1 with chemical compounds

• TBF1 produced in vitro yields protein-DNA complexes with (TTAGGG)n probes that have mobilities on native polyacrylamide gels identical to those produced by partially purified TBF alpha from yeast cells [3].

Physical interactions of TBF1

• In this study we show that the Tbf1p DNA-binding domain can target the Gal4 transactivation domain to a (TTAGGG)(n) sequence inserted in the yeast genome, supporting the model that Tbf1p binds this sub-telomeric repeat motif in vivo [4].

Other interactions of TBF1

• Together with Reb1p and Tbf1p, previously involved in the activity of Saccharomyces cerevisiae subtelomeric insulators, insulating potential emerges as a supplementary common property of General Regulatory Factors (GRFs) [6].

References