Accessibility control of T cell receptor gene rearrangement in developing thymocytesm - The TCR alpha/delta locus

The joining of T cell receptor (TCR) and immunoglobulin (Ig) gene segments through the process of V(D)J recombination occurs in a lineage-specific and developmental-stage-specific way during the early stages of lymphocyte dev elopment. Such developmental regulation is thought to be mediated through t he control of gene segment accessibility to the recombinase. We have studie d the regulation of V(D)J recombination at the TCR alpha/delta locus, becau se this locus provides a fascinating model in which distinct sets of gene s egments are activated at different stages of T cell development. The transc riptional enhancers E delta and E alpha have been implicated as critical re gulators that, in conjunction with other cis-acting elements, confer region -specific and developmental-stage-specific changes in gene segment accessib ility within TCR alpha/delta locus chromatin. Current work suggests that th ey may do so by functioning as regional modulators of histone acetylation.