Eri1 negatively regulates miRNAs in lymphocytes. (A) qRT-PCR analysis of miRNA expression in ICR/B6 Eri1^−/− NK (NK1.1⁺CD3ϵ⁻) cells purified by flow cytometry. (Left) miRNA levels in Eri1^−/− NK cells shown relative to WT (). (Right) Sum of measurements from 10 miRNAs () and Sno202 (□). Data were normalized to U6 snRNA. Graphs indicate mean ± SEM (N = 6, ICR/B6 littermates). (B) Northern blot analysis of miRNAs from Eri1 WT (WT, Eri1^+/+;CD4-cre), heterozygous (Het, Eri1^fl/+;CD4-cre), and knockout (KO, Eri1^fl/fl;CD4-cre) CD4⁺ T cells. Values indicate miRNA-specific signals quantified by phosphoimager, normalized to Arg-tRNA, and expressed relative to WT T cells. (C Left) qRT-PCR analysis of miRNA expression in Eri1-deficient (Eri1^fl/fl;CD4-cre) T cells transduced with retroviruses encoding Thy1.1 and ECFP () or Thy1.1 and Eri1-ECFP (). Total RNA was prepared from transduced Thy1.1⁺ T cells purified by FACS. Data were normalized to U6 snRNA and expressed relative to miRNA measured in WT (Eri1^+/+;CD4-cre) T cells transduced with ECFP retrovirus. (Right) Average of all miRNAs measured and Sno202 control. Columns show mean ± SEM (4 independent experiments). (D) Microarray comparison of miRNA expression patterns in WT and Eri1-deficient CD4⁺ T cells. Circles show average log₂ hybridization fluorescence intensity values for quantile-normalized data from 3 independent T-cell samples. Black diagonal lines show 2-fold intensity differences. (E) Small RNA read counts from WT and Eri1^−/− T-cell sequencing libraries. Dots show read counts at independent genomic loci with reads normalized to total genomic sequences in each library. Black lines indicate 5-fold expression differences. Circled dots show loci with > 90% posterior probability of a 5-fold expression difference between libraries. The location of these loci and gene origin of the most frequently cloned RNA from that locus are (left) Chr13:98860450-98860650, Rps18 pseudogene and (right) Chr8:73490090-73490290, Ell.