Abstract
B and T cell receptor gene assembly by V(D)J recombination is tightly regulated during lymphoid development. The mechanisms involved in this regulation are poorly understood. Here we show that nucleosomal DNA is refractory to V(D)J cleavage. However, the presence of HMG1, a chromatin-associated nonhistone DNA-binding protein, stimulates V(D)J cleavage of nucleosomal templates. This HMG1 stimulation is differentially affected by the rotational or translational positioning of the recombination signal sequence on the histone octamer, with cleavage of the 12 bp spacer RSS showing sensitivity to rotational position and the 23 bp spacer RSS affected by its displacement from the dyad. These results suggest that V(D)J recombination can be modulated by controlling substrate accessibility and cleavage at the level of an individual nucleosome.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Base Pairing
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DNA / chemistry
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DNA / metabolism*
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DNA-Binding Proteins / pharmacology
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Gene Expression Regulation
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Gene Rearrangement / drug effects*
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Genes, Immunoglobulin / genetics
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HeLa Cells
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Homeodomain Proteins / pharmacology
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Humans
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Mucin-5B
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Mucins / chemistry
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Mucins / pharmacology*
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Nuclear Proteins
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Nucleic Acid Conformation
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Nucleosomes / chemistry
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Nucleosomes / metabolism*
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Oligonucleotides / chemistry
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Oligonucleotides / pharmacology*
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Receptors, Antigen / chemistry
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Receptors, Antigen / genetics
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Receptors, Antigen / metabolism*
Substances
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DNA-Binding Proteins
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Homeodomain Proteins
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MUC5B protein, human
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Mucin-5B
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Mucins
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Nuclear Proteins
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Nucleosomes
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Oligonucleotides
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RAG2 protein, human
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Receptors, Antigen
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V(D)J recombination activating protein 2
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RAG-1 protein
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DNA