Demonstration of δRec-pseudo Jα rearrangement with deletion of the δ locus in a human stem-cell leukemia

Abstract

It has been hypothesized that a rearrangement between the δ recombining element (δRec) and a pseudo Jα gene serves to delete the TCR-δ locus before rearrangement of the TCR-α genes. We have now sequenced a direct, site-specific rearrangement between the δRec element and a pseudo Jα gene in a human leukemic stem-cell line. Putative 'N-sequence' addition was noted at the site of recombination, suggesting that this even occurred at the time when the enzyme(s) involved in N-region addition were active in this cell. This provides support for the view that deletion of the TCR-δ locus is required before rearrangement of the TCR-α chain genes.