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1970961 
Journal Article 
Asymmetric binding of histone H1 stabilizes MMTV nucleosomes and the interaction of progesterone receptor with the exposed HRE 
Vicent, GP; Melia, MJ; Beato, M 
2002 
Yes 
Journal of Molecular Biology
ISSN: 0022-2836
EISSN: 1089-8638 
324 
3 
501-517 
12445785 
WOS:000179670200010 
Packaging of mouse mammary tumor virus (MMTV) promoter sequences in nucleosomes modulates access of DNA binding proteins and influences the interaction among DNA bound transcription factors. Here we analyze the binding of historic H1 to MMTV mononucleosomes assembled with recombinant histones and study its influence on nucleosome structure and stability as well as on progesterone receptor (PR) binding to the hormone responsive elements (HREs). The MMTV nucleosomes can be separated into three main populations, two of which exhibited precise translational positioning. Histone H1 bound preferentially to the 5 distal nucleosomal DNA protecting additional 27-28 nt from digestion by micrococcal nuclease. Binding of histone H1 was unaffected by prior crosslinking of protein and DNA in nucleosomes with formaldehyde. Neither the translational nor the rotational nucleosome positioning was altered by histone H1 binding, but the nucleosomes were stabilized as judged by the kinetics of nuclease cleavage. Unexpectedly, binding of recombinant PR to the exposed distal HRE-I in nucleosomes was enhanced in the presence of histone H1, as demonstrated by band shift and footprinting experiments. This enhanced PR affinity may contribute to the reported positive effect of historic H1 on the hormonal activation of MMTV reporter genes. (C) 2002 Elsevier Science Ltd. All rights reserved. 
chromatosomes; linker histories; nuclear receptors; chromatin structure