Figure 1

Competition between H1 subtypes for a limited amount of DNA. (A) Competition between pairs of subtypes. The protein (total H1)/DNA ratio was 3:1 (w/w). This weight ratio is equivalent to ~0.09 H1 molecules per base pair or ~3 H1 molecules per DNA binding site (assuming a DNA binding site of 33 base pairs [42]). The whole pellet and 1/3 of the supernatant were run on the gel. The subtypes H1a-e and H1° are indicated on the left (a-e, 0). SAR, scaffold attachment region from the Drosophila histone cluster (657 bp); pUC19, HaeIII/HaeIII fragment from pUC19 (587 bp); i, input mixture of subtypes; p, pellet; s, supernatant. (B) Competition between three subtypes. (C) Competition with a protein/DNA ratio of 10:1 (w/w), equivalent to ~10 H1 molecules per DNA binding site. The whole pellet and supernatant were run on the gel.