Purification and characterization of a protein that binds to the recombination signal sequence of the immunoglobulin J kappa segment. |
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Authors: | Y Hamaguchi N Matsunami Y Yamamoto T Honjo |
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Affiliation: | Department of Medical Chemistry, Kyoto University Faculty of Medicine, Japan. |
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Abstract: | A protein that binds to the recombination signal sequence (RS) of the immunoglobulin J kappa segment was purified almost to homogeneity from the nuclear extract of a murine pre-B cell line 38B9. A similar binding protein was found in lymphoid cell lines but not in non-lymphoid cell lines. The binding activity was associated with a polypeptide with a molecular weight of 60,000. DNase I footprinting analysis demonstrated that this binding protein interacted with the heptamer and several 3' bases close to the heptamer. The Kd value of the J kappa RS binding protein to the J kappa RS was 1 nM. One base substitution in the heptamer of the J kappa RS greatly reduced the affinity of the J kappa RS binding protein. The high specificity of the binding site of the J kappa RS binding protein suggests that this protein may be involved in V-J recombination. |
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