Linker histone protects linker DNA on only one side of the core particle and in a sequence-dependent manner.
The protection against micrococcal nuclease digestion afforded to chromatosomal DNA by the presence of a linker histone (H1(o)) has been quantitatively measured in two reconstituted systems. We have used chromatosomes reconstituted at two distinct positions on a DNA fragment containing the 5S rRNA gene from Lytechinus variegatus and at a specific position on a sequence containing Gal4- and USF-binding sites. In all cases, we find asymmetric protection, with approximately 20 bp protected on one side of the core particle and no protection on the other. We demonstrated through crosslinking experiments that the result is not due to any sliding of the histone core caused by either linker histone addition or micrococcal nuclease cleavage. Because the core particle is itself a symmetric object, the preferred asymmetric location of a linker histone must be dictated by unknown elements in the DNA sequence.
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Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331-7305, USA.
Leuba
S H
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van Holde
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Zlatanova
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D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D003432:Cross-Linking Reagents; D004247:DNA / Q000235:genetics* / Q000378:metabolism*; D004275:DNA, Ribosomal / Q000235:genetics / Q000378:metabolism; D006657:Histones / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D011485:Protein Binding; D012341:RNA, Ribosomal, 5S / Q000235:genetics*; D012617:Sea Urchins / Q000235:genetics; D017422:Sequence Analysis, DNA
D003432:Cross-Linking Reagents; D004275:DNA, Ribosomal; D006657:Histones; D012341:RNA, Ribosomal, 5S; D004247:DNA