Wiest, D. | bioRxiv Science

bioRxiv2023

E-proteins set the threshold for optimal TCF1 expression during αβ T cell development.

Expression of T Cell Factor-1 (TCF1), encoded by Tcf7, regulates lineage fate decisions during T cell development. Here we demonstrate that E-proteins control the threshold of TCF1 expression required for development of T cells. E-proteins bind to five elements (EPEs) in the Tcf7 locus. The third element, EPE3, interacts directly with Tcf7 promoter in Hi-ChIP analyses, suggesting it is an active enhancer. CRISPR-ablation of EPE3 reduces TCF1 protein expression in precursor thymocytes by 2-fold and dramatically impairs development of {beta} and {gamma}{delta} T cells. Single cell gene expression analysis identified differentiation blocks at multiple CD4-CD8- stages and subsequent transition to CD4+CD8+ stage. These data identify E-proteins and EPE3 as critical for the optimal TCF1 expression required for T cell development.

immunology↗

bioRxiv2021

Loss of Zfp335 triggers cGAS/STING-dependent apoptosis of post-β selection pre-T cells

Production of a diverse peripheral T cell compartment requires massive expansion of the bone marrow progenitors that seed the thymus. There are two main phases of expansion during T cell development, following T lineage commitment at the DN2 stage and following successful rearrangement and selection for functional TCR{beta} chains in DN3 thymocytes, which promotes development of DN4 cells to the DP stage. Signals driving expansion of DN2 thymocytes are well studied, however, factors regulating the proliferation and survival of DN4 cells remain poorly understood. Here, we uncover an unexpected link between the transcription factor Zfp335 and control of cGAS/STING-dependent cell death in post-{beta}-selection DN4 thymocytes. Zfp335 controls survival by sustaining expression of Ankle2, which suppresses cGAS/STING-dependent cell death. Together, this study identifies Zfp335 as a key transcription factor controlling the survival of proliferating post-{beta}-selection thymocytes and demonstrates a key role for the cGAS/STING pathway driving apoptosis of developing T cells.

immunology↗