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Nucleosome structure completely inhibits in vitro cleavage by the V(D)J recombinase
Author(s) -
Golding Amit,
Chandler Simon,
Ballestar Esteban,
Wolffe Alan P.,
Schlissel Mark S.
Publication year - 1999
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/18.13.3712
Subject(s) - biology , recombinase , nucleosome , cleavage (geology) , in vitro , microbiology and biotechnology , genetics , biophysics , chromatin , dna , recombination , gene , paleontology , fracture (geology)
Lineage specificity and temporal ordering of immunoglobulin (Ig) and T‐cell receptor (TCR) gene rearrangement are reflected in the accessibility of recombination signal sequences (RSSs) within chromatin to in vitro cleavage by the V(D)J recombinase. In this report, we investigated the basis of this regulation by testing the ability of purified RAG1 and RAG2 proteins to initiate cleavage on positioned nucleosomes containing RSS substrates. We found that nicking and double‐strand DNA cleavage of RSSs positioned on the face of an unmodified nucleosome are entirely inhibited. This inhibition was independent of translational position or rotational phase and could not be overcome either by addition of the DNA‐bending protein HMG‐1 or by the use of hyperacetylated histones. We suggest that the nucleosome could act as the stable unit of chromatin which limits recombinase accessibility to potential RSS targets, and that actively rearranging gene segments might be packaged in a modified or disrupted nucleosome structure.