Figure 4.

Requirement of histone H4 N-terminal tail for NURF activity. (A) Stimulation of ATPase activity of NURF by nucleosomes. ATPase assays contained WT nucleosomes or nucleosomes lacking histone tails, as indicated. ATPase activity was measured by hydrolysis of [α-P³²]ATP to [α-P³²]ADP and visualized by TLC. ATPase assays were conducted in the presence of GST or GST-H4 tail proteins, as indicated. (B) Nucleosome sliding assay. hsp70 mononucleosomes (359 bp) reconstituted from WT or mutant histones were incubated with NURF in the presence or absence of ATP and electrophoresed (4% polyacrylamide gel) in TE buffer. WT mononucleosomes were reacted with NURF and ATP in the presence of GST or GST-H4 tail proteins, as indicated, before electrophoresis.