Telomere binding proteins

The control of telomerase must be important. The enzyme is active in early embryonic cells and some stem cells. However, most normal cells have little or no telomerase activity and lose telomere length throughout their lifespan with eventual growth arrest.448/454/457 On the other hand, excessive telomerase activity may induce cancer.451/458/459 Certain mutations in the telomerase guide RNA can cause greatly increased telomerase activity.459 The control of telomerase is still poorly understood but involves specific telomere-binding proteins 448,454,460-460b... 

Tetrabutylammonium chloride TATA-binding protein telomere-binding protein Trichloroacetic acid tricarboxylic acid T-cell receptor... 

Figure 1 Cartoon showing the T-loop and D-loop and associated telomere binding proteins (18).

Proteins may also modulate the formation of G-quadruplexes. The beta-subunit of the Oxytricha telomere-binding protein acts as a molecular chaperone to... 

R. Giraldo and D. Rhodes, The yeast telomere-binding protein RPl binds to and promotes the formation of DNA quadruplexes in telomeric DNA, The EMBO /., 1994, 13(10), 2411-2420. 

R. Giraldo, M. Suzuki, L. Chapman and D. Rhodes, Promotion of parallel DNA quadruplexes by a yeast telomere binding protein a circular dichro-ism study, Proc. Natl. Acad. Sci. USA, 1994, 91, 7658-7662. 

L. Laporte and G.J. Thomas Jr., Structural basis of DNA recognition and mechanism of quadruplex formation by the b subunit of the Oxytricha telomere-binding protein. Biochemistry, 1998, 37, 1327-1335. 

S. cerevisiae felomers have 350 base pairs confaining fhe sequences (TGj 3 / C 3A) as well as one or more copies of a 6.7-kb nonrepefihve sequence and ofher elemenfs. In many species fhe repehfive felo-meric sequences have 3 poly(G) fails at the ends of fhe DNA molecules. These fails are able to form G quarfef sfrucfures (Fig. 5-26 and Chapter 5, Sechon C,4). A variety of telomere-binding proteins have been isolated. " Some of fhese bind to G quartet struc-... 

One of the signs of Werner s progeria is rapid aging of the skin. Skin fibroblasts of Werner s progeria patients have unusually short telomeres, a phenotype that can be rescued in vitro by expression of the catalytic subunit of telomerase. Molecular genetics studies have shown that Werner s progeria arises from defects in WRN, a helicase that can physically associate with telomere-binding proteins. 

Giraldo R, Suzuki M, Chapman L, Rhodes D. Promotion and parallel DNA quadmplexes by a yeast telomere binding protein a circular dichronism study. Proc Natl Acad Sci USA. 1994 91 7658-62. 

Prescott JD, DuBois ML, Prescott DM. Evolution of the scrambled germline gene encoding alpha-telomere binding protein in three hypertrichous ciliates. Chromosoma. 

Baker AM, Fu Q, Hayward W, Lindsay SM, Fletcher TM. The Myb/SANT domain of the telomere-binding protein TRF2 alters chromatin stracture. Nucleic Acids Res. 2009 37 5019-31. 

Horvath MP. Evolution of telomere-binding proteins. In Nosek J, Tomaska L, editors. Origin and evolution of telomeres. Austin, TX Landes Bioscience 2008. p. 83-99. 

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