The histone octamer is invisible when NF-kappaB binds to the nucleosome.
The transcription factor NF-kappaB is involved in the transcriptional control of more than 150 genes, but the way it acts at the level of nucleosomal templates is not known. Here we report on a study examining the interaction of NF-kappaB p50 with its DNA recognition sequence in a positioned nucleosome. We demonstrate that NF-kappaB p50 was able to bind to the nucleosome with an apparent association constant close to that for free DNA. In agreement with this, the affinity of NF-kappaB p50 binding does not depend on the localization of its recognition sequence relative to the nucleosome dyad axis. In addition, the binding of NF-kappaB p50 does not induce eviction of histones and does not perturb the overall structure of the nucleosome. The NF-kappaB p50-nucleosome complex exhibits, however, local structural alterations within the NF-kappaB p50 recognition site. Importantly, these alterations were very similar to those found in the NF-kappaB p50-DNA complex. Our data suggest that NF-kappaB p50 can accommodate the distorted, bent DNA within the nucleosome. This peculiar property of NF-kappaB p50 might have evolved to meet the requirements for its function as a central switch for stress responses.
Laboratoire de Biologie Moléculaire et Cellulaire de la Différenciation, INSERM U309, Institut Albert Bonniot, Domaine de la Merci, 38706 La Tronche Cedex, France.
Dimitar
D
Angelov
François
F
Lenouvel
Fabienne
F
Hans
Christoph W
CW
Müller
Philippe
P
Bouvet
Jan
J
Bednar
Evangelos N
EN
Moudrianakis
Jean
J
Cadet
Stefan
S
Dimitrov
D000818:Animals; D001665:Binding Sites; D020285:Cryoelectron Microscopy; D004247:DNA / Q000737:chemistry; D003850:Deoxyribonuclease I / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D006657:Histones / Q000737:chemistry*; D017665:Hydroxyl Radical; D007834:Lasers; D016328:NF-kappa B / Q000737:chemistry* / Q000378:metabolism*; D052002:NF-kappa B p50 Subunit; D009707:Nucleosomes / Q000378:metabolism*; D009841:Oligonucleotides / Q000737:chemistry; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D013997:Time Factors; D014158:Transcription, Genetic; D014466:Ultraviolet Rays; D014981:Xenopus; D014982:Xenopus laevis
D006657:Histones; D016328:NF-kappa B; D052002:NF-kappa B p50 Subunit; D009707:Nucleosomes; D009841:Oligonucleotides; D017665:Hydroxyl Radical; D004247:DNA; D003850:Deoxyribonuclease I