Dissection of the unusual structural and functional properties of the variant H2A.Bbd nucleosome.

The histone variant H2A.Bbd appeared to be associated with active chromatin, but how it functions is unknown. We have dissected the properties of nucleosome containing H2A.Bbd. Atomic force microscopy (AFM) and electron cryo-microscopy (cryo-EM) showed that the H2A.Bbd histone octamer organizes only approximately 130 bp of DNA, suggesting that 10 bp of each end of nucleosomal DNA are released from the octamer. In agreement with this, the entry/exit angle of the nucleosomal DNA ends formed an angle close to 180 degrees and the physico-chemical analysis pointed to a lower stability of the variant particle. Reconstitution of nucleosomes with swapped-tail mutants demonstrated that the N-terminus of H2A.Bbd has no impact on the nucleosome properties. AFM, cryo-EM and chromatin remodeling experiments showed that the overall structure and stability of the particle, but not its property to interfere with the SWI/SNF induced remodeling, were determined to a considerable extent by the H2A.Bbd docking domain. These data show that the whole H2A.Bbd histone fold domain is responsible for the unusual properties of the H2A.Bbd nucleosome.

Keywords

Amino Acid Sequence Animals Binding Sites Chromatin Assembly and Disassembly Chromosomal Proteins Non-Histone Cryoelectron Microscopy Histones Microscopy Molecular Sequence Data Protein Folding Quaternary Tertiary

DNA Atomic Force Mutation Nucleosomes Protein Structure Recombinant Proteins Variation (Genetics) Xenopus Proteins Xenopus laevis

Domains

Life Sciences [q-bio] Genetics

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Figs1-8.pdf (1.4 Mo)

H2A.Bbd.pdf (467.93 Ko)

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https://www.hal.inserm.fr/inserm-00335077

Submitted on : Tuesday, October 28, 2008-1:54:40 PM

Last modification on : Thursday, October 13, 2022-3:06:38 PM

Long-term archiving on: Tuesday, September 18, 2012-12:25:18 PM

Dates and versions

inserm-00335077 , version 1 (28-10-2008)

Identifiers

HAL Id : inserm-00335077 , version 1
DOI : 10.1038/sj.emboj.7601310
PRODINRA : 248933
PUBMED : 16957777

Cite

Cécile-Marie Doyen, Fabien Montel, Thierry Gautier, Hervé Menoni, Cyril Claudet, et al.. Dissection of the unusual structural and functional properties of the variant H2A.Bbd nucleosome.. EMBO Journal, 2006, 25 (18), pp.4234-44. ⟨10.1038/sj.emboj.7601310⟩. ⟨inserm-00335077⟩

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