CD4 and CD8 mark helper and cytotoxic T cell lineages, respectively, and serve as coreceptors for MHC-restricted TCR recognition. How coreceptor expression is matched with TCR specificity is central to understanding CD4/CD8 lineage choice, but visualising coreceptor gene activity in individual selection intermediates has been technically challenging. It therefore remains unclear whether the sequence of coreceptor gene expression in selection intermediates follows a stereotypic pattern, or is responsive to signaling. Here we use single cell RNA sequencing (scRNA-seq) to classify mouse thymocyte selection intermediates by coreceptor gene expression. In the unperturbed thymus, Cd4+Cd8a- selection intermediates appear before Cd4-Cd8a+ selection intermediates, but the timing of these subsets is flexible according to the strength of TCR signals. Our data show that selection intermediates discriminate MHC class prior to the loss of coreceptor expression and suggest a model where signal strength informs the timing of coreceptor gene activity and ultimately CD4/CD8 lineage choice.

• MeSH
• Lymphocyte Activation genetics   MeSH
• Principal Component Analysis MeSH
• Cell Differentiation immunology   MeSH
• Cell Lineage immunology   MeSH
• CD4-Positive T-Lymphocytes cytology   immunology   MeSH
• CD8-Positive T-Lymphocytes cytology   immunology   MeSH
• Cytokines metabolism   MeSH
• DNA-Binding Proteins metabolism   MeSH
• Histocompatibility Antigens metabolism   MeSH
• RNA, Messenger genetics   metabolism   MeSH
• Mice, Inbred C57BL MeSH
• Core Binding Factor Alpha 3 Subunit metabolism   MeSH
• Receptors, Antigen, T-Cell metabolism   MeSH
• Gene Expression Regulation MeSH
• Signal Transduction MeSH
• Thymus Gland cytology   immunology   MeSH
• Transcription Factors metabolism   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, N.I.H., Extramural MeSH