Small RNA profiling of wildtype and Eri1-deficient mouse T cells

Natural killer (NK) cells play a critical role in early host defense to infected and transformed cells. Here we show that mice deficient in Eri1, a conserved 3’-to-5’ exoribonuclease that represses RNA interference, have a cell-intrinsic defect in NK cell development and maturation. Eri1–/– NK cells displayed delayed acquisition of Ly49 receptors in the bone marrow and a selective reduction in Ly49D and Ly49H activating receptors in the periphery. Eri1 was required for immune-mediated control of mouse cytomegalovirus (MCMV) infection. Ly49H+ NK cells deficient in Eri1 failed to expand efficiently during MCMV infection, and virus-specific responses were also diminished among Eri1–/– T cells. We identified miRNAs as the major endogenous small RNA target of Eri1 in mouse lymphocytes. Both NK and T cells deficient in Eri1 displayed a global, sequence-independent increase in miRNA abundance. Ectopic Eri1 expression rescued defective miRNA expression in mature Eri1–/– T cells. Thus, mouse Eri1 regulates miRNA homeostasis in lymphocytes and is required for normal NK cell development and anti-viral immunity. Overall design: Small RNA profiling from wildtype and Eri1-deficient mouse CD4+ T cells

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Thomas MF, Abdul-Wajid S, Panduro M, Babiarz JE, Rajaram M, Woodruff P, Lanier LL, Heissmeyer V, Ansel KM