An unresolved question in the organization of mammalian telomeres is whether specific telomeric proteins compete with the histone octamer for binding to telomeric sequences or whether they cooperate to form a telomeric protective structure. By means of in vitro model systems we previously demonstrated that TRF1 is able to recognize nucleosomal binding sites and to alter nucleosome structure. We show that, unlike TRF1, TRF2 is unable to bind to nucleosomal binding sites, suggesting that TRF2 and the histone octamer compete for binding to telomeres. To investigate how TRF2 interplays with telomeric nucleosomes, we set up a model system to assemble telomeric nucleosomal arrays by using Drosophila embryonic extracts. We found that telomeric nucleosomes are spaced every 155±5 bp, indicating that the short nucleosomal spacing found in vivo is a sequence-dependent feature. Remarkably, when added to the Drosophila extracts TRF2 increases nucleosomal repeat length to about 195±5 bp, indicating that TRF2 may preferentially position between nucleosomes.

TRF2 NEGATIVELY AFFECTS NUCLEOSOME ASSEMBLY ON TELOMERIC SEQUENCES / Galati, Alessandra; F., Magdinier; S., Dimitrov; V., Colasanti; Savino, Maria; E., Gilson; Cacchione, Stefano. - STAMPA. - (2009), pp. 215-215. (Intervento presentato al convegno TELOMERES & TELOMERASE tenutosi a COLD SPRING HARBOR LABORATORY, COLD SPRING HARBOR, NEW YORK, USA nel 28 APRILE-2 MAGGIO 2009).

TRF2 NEGATIVELY AFFECTS NUCLEOSOME ASSEMBLY ON TELOMERIC SEQUENCES

GALATI, Alessandra;SAVINO, Maria;CACCHIONE, Stefano
2009

Abstract

An unresolved question in the organization of mammalian telomeres is whether specific telomeric proteins compete with the histone octamer for binding to telomeric sequences or whether they cooperate to form a telomeric protective structure. By means of in vitro model systems we previously demonstrated that TRF1 is able to recognize nucleosomal binding sites and to alter nucleosome structure. We show that, unlike TRF1, TRF2 is unable to bind to nucleosomal binding sites, suggesting that TRF2 and the histone octamer compete for binding to telomeres. To investigate how TRF2 interplays with telomeric nucleosomes, we set up a model system to assemble telomeric nucleosomal arrays by using Drosophila embryonic extracts. We found that telomeric nucleosomes are spaced every 155±5 bp, indicating that the short nucleosomal spacing found in vivo is a sequence-dependent feature. Remarkably, when added to the Drosophila extracts TRF2 increases nucleosomal repeat length to about 195±5 bp, indicating that TRF2 may preferentially position between nucleosomes.
2009
0879699140
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/53666
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