IMGT/JunctionAnalysis: IMGT Standardized Analysis of the V-J and V-D-J Junctions of the Rearranged Immunoglobulins (IG) and T Cell Receptors (TR)

INTRODUCTION IMGT/JunctionAnalysis is the online IMGT tool for the detailed and standardized analysis of the junctions between the variable (V), diversity (D), and joining (J) genes (V-J and V-D-J junctions) of the rearranged immunoglobulin (IG) or antibody and T cell receptor (TR) variable domains. The V-(D)-J junctions comprise the rearranged CDR3-IMGT and its anchors 2nd-CYS 104 and J-PHE or J-TRP 118. The diversity of the junctions that determines the antigen receptor specificity results from complex molecular mechanisms that occur at the DNA level during the IG and TR synthesis and create combinatorial diversity, N-diversity and, for IG, somatic hypermutations. The annotation of V-J or V-D-J junctions in rearranged IG and TR sequences represents a huge challenge due to its uniqueness and complexity. IMGT/JunctionAnalysis has been a major breakthrough by providing, for the first time, a very detailed and accurate analysis of the junctions. The tool, whose use is described here, identifies the D genes in the IGH, TRB, and TRD junctions, the trimmed nucleotides (nt) at the end of the genes which recombine, and the palindromic P regions in the absence of gene trimming. It delimits the N regions that result from the N-diversity, calculates the ratio of G+C nucleotides in the N regions, and evaluates the number of somatic hypermutations for each gene within the junction.