Skip to main content
. 2011 May 4;2:12. doi: 10.3389/fimmu.2011.00012

Figure 2.

Figure 2

V(D)J recombination and the formation of excision circles. (A) Sequential rearrangements in the TCRAD locus. Following V(D)J recombination of TCRD, the whole locus is then preferentially deleted by δREC–ψJα rearrangements in the αβ+ T-cell lineage. This gives rise to a δREC–ψJα signal joint on an excision circle (TREC) and a δREC–ψJα coding joint in the genome. The coding joint is deleted from the genome by TCRA (Vα-Jα) rearrangements and is then located on a TREC as well. (B) V(D)J recombination on the IGK locus results in a VJκ coding joint. Subsequent rearrangement between the intronRSS and the Kde elements can render the IGK allele non-functional by deleting the Cκ exons and the enhancers. Consequently, the coding joint precludes any further rearrangements in the IGK locus and therefore remains present in the genome, whereas an intronRSS–Kde signal joint is formed on an excision circle (KREC). (C) Oligonucleotide characteristics for TREC, KREC, and control gene quantification (Pongers-Willemse et al., 1998; Hazenberg et al., 2000; Dik et al., 2005; van Zelm et al., 2007a).