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XB-ART-11953
Mol Cell Biol 1999 Dec 01;1912:8591-603. doi: 10.1128/MCB.19.12.8591.
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NF-Y associates with H3-H4 tetramers and octamers by multiple mechanisms.

Caretti G , Motta MC , Mantovani R .


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NF-Y is a CCAAT-binding trimer with two histonic subunits, NF-YB and NF-YC, resembling H2A-H2B. We previously showed that the short conserved domains of NF-Y efficiently bind to the major histocompatibility complex class II Ea Y box in DNA nucleosomized with purified chicken histones. Using wild-type NF-Y and recombinant histones, we find that NF-Y associates with H3-H4 early during nucleosome assembly, under conditions in which binding to naked DNA is not observed. In such assays, the NF-YB-NF-YC dimer forms complexes with H3-H4, for whose formation the CCAAT box is not required. We investigated whether they represent octamer-like structures, using DNase I, micrococcal nuclease, and exonuclease III, and found a highly positioned nucleosome on Ea, whose boundaries were mapped; addition of NF-YB-NF-YC does not lead to the formation of octameric structures, but changes in the digestion patterns are observed. NF-YA can bind to such preformed DNA complexes in a CCAAT-dependent way. In the absence of DNA, NF-YB-NF-YC subunits bind to H3-H4, but not to H2A-H2B, through the NF-YB histone fold. These results indicate that (i) the NF-Y histone fold dimer can efficiently associate DNA during nucleosome formation; (ii) it has an intrinsic affinity for H3-H4 but does not form octamers; and (iii) the interactions between NF-YA, NF-YB-NF-YC, and H3-H4 or nucleosomes are not mutually exclusive. Thus, NF-Y can intervene at different steps during nucleosome formation, and this scenario might be paradigmatic for other histone fold proteins involved in gene regulation.

???displayArticle.pubmedLink??? 10567583
???displayArticle.pmcLink??? PMC84987
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Species referenced: Xenopus laevis
Genes referenced: h2ac21 h2bc21 nfya nfyb nfyc

References [+] :
Alevizopoulos, A proline-rich TGF-beta-responsive transcriptional activator interacts with histone H3. 1995, Pubmed