Figure 4.

Single, randomly positioned nucleosome-free gaps strongly affect EPC on 601₁₇₇ arrays. (A) Transcription of saturated 601_177×N nucleosomal arrays (N = 4, 7, 8 or 10 nucleosomes in the array) and the same arrays missing one nucleosome in random positions (-1RN). Analysis of labeled transcripts by denaturing PAGE. The rates of EPC were measured as described in Figure 3A. Removal of a single nucleosome from any position along the nucleosome arrays with more than seven nucleosomes leads to more efficient EPC. (B) Quantitative analysis of the specific transcripts shown in Figure 4A. Error bars indicate standard deviations based on four independent measurements using two different reconstitutes (see Supplementary Table S2 for the results of t-test).