Fig. 8: Model for biogenesis and function of regular nucleosome arrays.

Transcription is strongly disruptive to nucleosome arrays and it takes ISWI-, Chd1- and/or INO80- remodelers to reinstate array architecture. Proper histone density is indispensable for spacing as neither DNA sequence-based nucleosome positioning nor the clamping activity of remodelers suffices. Remodelers also position the +1 nucleosome, thereby sharpening the site of transcription initiation (green arrows). Regularly spaced nucleosome arrays prevent cryptic transcription (red arrows), DNA damage, ectopic recombination and transposon integration within the gene body.