VARIABLE GENE SEGMENT-SPECIFIC N-INSERTIONS AT THE SIGNAL JOINT OF T-CELL RECEPTOR V-BETA-D-BETA RECOMBINATIONS

The V(D)J recombination of immunoglobulin and a T-cell receptor genera tes two species of DNA junctions, a coding joint and a signal joint. N on-templated nucleotides (N-nucleotides) are inserted in these DNA jun ctions. We analyzed the N-insertion at signal joints generated by the V beta-D beta recombinations. N-insertions were detected at signal joi nts of V beta 2, V beta 3, V beta 10, V beta 18 and V beta 14 but not in V beta 8 and V beta 7. These data show that the N-insertion at sign al joints is dependent on the V beta locus used for the recombination. We suggest that the regional chromosomal configuration may differ in recombinase accessibility. (C) 1998 Elsevier Science B.V. All rights r eserved.