title: E proteins are required to activate germline transcription of the TCR Vbeta8.2 gene.
abstract: Each TCR Vbeta gene is regulated by an individual Vbeta promoter, which becomes active prior to V(D) J recombination and drives germline transcription. It has been shown that Vbeta gene locus activation and recombination are dependent on the Vbeta promoter. However, transcription factors that regulate Vbeta germline transcription remain largely undefined. A major challenge in studying Vbeta gene germline transcription is the quantitative assessment of relatively low-level transcripts in T-cell progenitors. Here we used the established Vbeta8.2(CD2) knock-in mouse model to assess functions of E-protein transcription factors in Vbeta8.2 germline transcription. We show that E proteins are required for the activation but not the maintenance of the Vbeta8.2 germline transcription during thymocyte development. The activation of Vbeta8.2 germline transcription depends more on the E proteins encoded by the E2A gene than by the HEB gene. We further show that IL-7 receptor (IL-7R)-mediated signals are essential for Vbeta8.2 germline transcription. We provide evidence that IL-7R expression is only partially controlled by E2A, suggesting a role for E2A in driving Vbeta8.2 germline transcription independent of IL-7R activation.
authors.affiliation: Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA.
authors.forename: Jingquan
authors.initials: J
authors.lastname: Jia
authors.forename: Meifang
authors.initials: M
authors.lastname: Dai
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhuang
mesh_terms: D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D055879:Gene Knock-In Techniques; D019674:Genes, T-Cell Receptor beta; D051379:Mice; D008817:Mice, Mutant Strains; D009154:Mutation; D010446:Peptide Fragments / Q000235:genetics*; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics*; D020395:Receptors, Interleukin-7 / Q000276:immunology / Q000378:metabolism*; D011995:Recombination, Genetic; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D015533:Transcriptional Activation; D015854:Up-Regulation
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D010446:Peptide Fragments; D016693:Receptors, Antigen, T-Cell, alpha-beta; D020395:Receptors, Interleukin-7; C109168:T-cell receptor Vbeta 8.2; C489532:Tcf12 protein, mouse; C075668:Tcf3 protein, mouse