Global derepression of miR-142-3p, but not miR-142-5p, targets in miR-142^−/− B cells. (A) Analysis of the effect of miR-142 deletion on global gene expression. SylArray plot analysis for the seed complementary region (SCR) words corresponding to 2 7-mer seeds of miR-142-3p (marked by black arrows) and 2 7-mer seeds of miR-142-5p (marked by gray arrows). Log₁₀-transformed enrichment P values for each SCR word, relative to P values of all other words, are plotted on the y-axis, against the ranked gene list on the x-axis (left, the most upregulated in KO vs WT genes; right, the most downregulated in KO vs WT genes). (B) Analysis of mature miR-142-5p and miR-142-3p expression in C57BL/6 B-cell subsets by quantitative reverse-transcription polymerase chain reaction. B-cell fractions were sorted by FACS from spleen (SP) and peritoneal cavity (PC). Expression level of miR-142-5p in liver was arbitrarily set to 1. SnoRNA234 levels were used for normalization. (C) Diagrams (left) and sequence alignments (right) of miR-142-3p putative binding sites in the 3′ UTRs of BAFF-R, RAG1, and WASL predicted by the TargetScan algorithm. (D) Validation of BAFF-R, RAG1, and WASL as direct miR-142-3p targets by 3′ UTR luciferase reporter assay. Relative expression of WT and mutated BAFF-R, RAG1, and WASL 3′ UTR reporter constructs upon cotransfection with either miR-142 expressing plasmid or empty control vector. Results are shown as means ± SD and are representative of at least 2 independent experiments. P values were calculated using 2-way analysis of variance. **P ≤ .01; ***P ≤ .001; ****P ≤ .0001.