Km. Janowski et al., IDENTIFICATION OF A DNA SEGMENT EXHIBITING REARRANGEMENT MODIFYING EFFECTS UPON TRANSGENIC DELTA-DELETING ELEMENTS, The Journal of experimental medicine, 186(1), 1997, pp. 91-100
Control of the rearrangement and expression of the T cell receptor alp
ha and delta chains is critical for determining T cell type. The proce
ss of delta deletion is a candidate mechanism for maintaining separati
on of the alpha and delta loci. Mice harboring a transgenic reporter d
elta deletion construct show alpha/beta T cell lineage-specific use of
the transgenic elements. A 48-basepair segment of DNA, termed HPS1A,
when deleted from this reporter construct, loses tight lineage-specifi
c rearrangement control of transgenic elements, with abundant rearrang
ements of transgenic delta-deleting elements now in gamma/delta T cell
s. Furthermore, HPS1A augments recombination frequency of extrachromos
omal substrates in an in vitro recombination assay. DNA binding protei
ns recognizing HPS1A have been identified and are restricted to early
B and T cells, during the time of active rearrangement of endogenous T
CR and immunoglobulin loci. These data are consistent with delta delet
ion playing an important role in maintaining separate TCR alpha and de
lta loci.