Figure 7.

Nt GTBP1 Inhibits Telomeric Strand Invasion in Vitro.

(A) Schematic representation of full-length and deletion mutants of GTBP1.

(B) Strand invasion assay. Increasing concentrations of GTBP1 derivatives (0, 0.2, 0.4, 0.6, and 0.8 μM) were incubated with a ³²P-labeled single-stranded (TTTAGGG)₈ repeat probe with T-vector plasmid containing double-stranded (TTTAGGG)₇₀ telomere repeats. The degree of invasion of the single-stranded telomeric probe into the plasmid was determined by the shifted band intensity. The first “−” lane of each gel contained radiolabeled PT8 without protein. The graph in the bottom panel shows relative intensities of shifted bands.

(C) Binding activities of full-length and deletion mutants of GTBP1 to single-strand telomere sequences. Various concentrations (0, 0.2, 0.4, 0.6, and 0.8 μM) of GTBP1 derivatives were analyzed with radiolabeled single-stranded (TTTAGGG)₈ (PT8) repeats.

[See online article for color version of this figure.]