Paris
Malade% TheT cell receptor (TCR)-a and -6 loci are contained on the same chromosomal region, and yet are developmentally and genetically independent. The first element of the J a cluster (YJa) is the site of an active rearrangement in the human thymus (6Rec-YJa rearrangement) and is localized downstream of a region expressed as a germ-line sterile transcript (TEA) in the human developing thymus.We hypothesized that the transcription of TEA could be indicative of (or responsible for) the opening of the J a t o theV(D)J recombinase and undertook to analyze cis-acting sequences controlling the TEA transcription. The promoter of TEA was characterized. It was part of a region that is highly conserved between human and mouse and contained many sites for the putative binding of T cell-specific transcription factors. The in vitro activity of this promoter was dependent on the association with an enhancer. A strong DNase I hypersensitive site was found in the vicinity of this promoter again suggesting the possible presence of protein-DNA interactions in this region. The implications of these results in the general perspective of TCR-a/6 gene regulation is discussed.
* This study was supported by INSERM and Association de
Recherche sur le Cancer.