Figure 5.

SWI/SNF alters the path of DNA bending around the histone octamer (A) The same core 5S DNA sequence as in Fig. 1 was end-labeled (lanes 2–4) or body-labeled (lanes 5–10), reconstituted into nucleosome cores, and digested with DNase I. Mock-reconstituted DNA is shown in lanes 2 and 5. 25 ng (12.5 nM) of total nucleosomes (probe plus donor oligonucleosomes) was incubated as before, followed by digestion with 0.05 unit (lanes 1, 5), 0.5 unit (lanes 3, 4), 1 unit (lane 8), 2 units (lane 9), or 10 units (lane 10) of DNase I; 1 mM Mg-ATP is present in lanes 4 and 7. (B) Body-labeled (lanes 1–5) and end-labeled (lanes 6–10) reconstituted probes were incubated in the presence or the absence of 2.5 nM SWI/SNF and/or ATP followed by digestion with 10 units (lanes 2–5) or 0.5 unit (lanes 7–10) of DNase I. Mock reconstitutions were digested with 1 unit (lane 1) and 0.05 unit (lane 6) of DNase I. (C) Reactions were performed as in B with the body-labeled reconstituted probe (using 10 units of DNase I) except that ATP is present in all lanes and 7.5 nM SWI/SNF is used in lane 4. Note the single 10-nucleotide digestion product kept in the gel.