Alternative Splicing Networks Regulated by Signaling in Human T Cells

The formation and execution of a productive immune response requires, among many things, the maturation of competent T cells and a robust change in cellular activity upon antigen challenge. Such changes in cellular function require regulated alterations of protein expression. Much work has previously gone into defining the transcriptional changes that regulate protein expression during T cell development and antigen stimulation. Here we describe a parallel pathway of gene regulation that occurs during T cell stimulation, namely alternative splicing. Specifically, we use RNA-Seq to identify 178 exons in 168 genes that exhibit robust changes in inclusion in response to a stimulation of a human T cell line. Interestingly, these signal-responsive genes are enriched for functions related to immune response including, cell trafficking, inflammatory and immune response, immunologic disease and several cell signaling pathways. The vast majority of these genes also exhibit different isoform expression in naive and activated primary T cells. Comparison of the responsiveness of splicing to various stimuli in the cultured and primary T cells reveal important insight into the diversity of signaling pathways that control splicing. Using this data we are able to classify signal-responsive exons into at least three distinct networks. Importantly, we find that each regulatory network is characterized by distinct sequence hallmarks, further suggesting independent regulatory mechanisms. We utilize high-throughput RNA sequencing (RNA-Seq) to investigate global changes in alternative splicing in a cultured T cell line and in primary human T cells. We identify 178 genes that are predicted to exhibit robust signal-induced changes in isoform expression in cultured T cells.