The IL-7 receptor controls the accessibility of the TCR gamma locus by Stat5 and histone acetylation

The IL-7 receptor (IL-7R) plays critical roles in expansion and V(D)J recom bination during lymphocyte development. Here we demonstrate that cytokine s timulation rapidly recruits Stat5 and transcriptional coactivators to the J y germline promoter and induces histone acetylation, germline transcription , and accessibility in Ba/F3 cells. We also show that histone acetylation o f the TCR gamma locus is significantly reduced in IL-7R-deficient thymocyte s and that the introduction of active Stat5 restores the histone acetylatio n and accessibility of the locus. Furthermore, treatment with histone deace tylase inhibitor recovers the histone acetylation and accessibility in IL-7 R-deficient thymocytes. Therefore, these results suggest that Stat5 may rec ruit the transcriptional coactivators to the Jy germline promoter and contr ol the accessibility of the TCR gamma locus by histone acetylation.