show Abstracthide AbstractWe investigated the role of RNMT in T cells using an Rnmt conditional knockout mouse model. We report that the mRNA cap methyltransferase, RNMT, supports naïve T cell survival and activation-induced proliferation. We demonstrate that RNMT has gene-specific impacts in T cells, selectively regulating expression of terminal polypyrimidine tract (TOP) mRNAs which are targets of the m7G-cap binding protein LARP1. These ribosome footprinting experiments investigate the effect of Rnmt cKO on the activated CD4 T cell transcriptome and translatome. Overall design: Sequencing of rRNA-depleted RNA and ribosome protected fragments from 20 hour activated CD4 T cells from Rnmt fl/fl CD4cre (Rnmt cKO) and Rnmt fl/fl (control) mice.