Autoregulated splicing of <i>TRA2</i> β programs T cell fate in response to antigen-receptor stimulation
Timofey A. Karginov, Antoine Ménoret, Nathan K. Leclair, Andrew G. Harrison, Karthik Chandiran, Jenny E. Suarez-Ramirez, Marina Yurieva, Keaton Karlinsey, Penghua Wang, Rachel J. O’Neill, Patrick A. Murphy, Adam J. Adler, Linda S. Cauley, Olga Anczuków, Beiyan Zhou, Anthony T. Vella
Abstract
T cell receptor (TCR) sensitivity to peptide–major histocompatibility complex (MHC) dictates T cell fate. Canonical models of TCR sensitivity cannot be fully explained by transcriptional regulation. In this work, we identify a posttranscriptional regulatory mechanism of TCR sensitivity that guides alternative splicing of TCR signaling transcripts through an evolutionarily ultraconserved poison exon (PE) in the RNA-binding protein (RBP) TRA2β in mouse and human. TRA2 β - PE splicing, seen during cancer and infection, was required for TCR-induced effector T cell expansion and function. Tra2 β-PE skipping enhanced T cell response to antigen by increasing TCR sensitivity. As antigen levels decreased, Tra2 β-PE reinclusion allowed T cell survival. Finally, we found that TRA2 β-PE was first included in the genome of jawed vertebrates that were capable of TCR gene rearrangements. We propose that TRA2 β - PE splicing acts as a gatekeeper of TCR sensitivity to shape T cell fate.