Project description:In order to identify miR-21 targets by a biochemical high-throughput method, we immunopurified RISC Complex and associated mRNAs in both control and miR-21 overexpressing Jurkat cells. Following transduction of miR-21 encoding construct (or a cognate control vector) in Jurkat cells, we used microarray technology to profile Total RNA, AGO2 Immunopurified RNA and control IgG purified RNA.
Project description:MiR-21 is an important suppressor of T-cell apoptosis that is also widely overexpressed in many types of cancers. The exact mechanisms related to the anti-apoptotic effect of miR-21 is not well understood. In this study, we applied AGO2 RNA Immunoprecipitation followed by gene expression profiling (RIP-Chip) in Jurkat cells to identify apoptosis-associated miR-21 target genes. We showed that expression of miR-21 rapidly increases upon αCD3/αCD28 activation of Jurkat cells. Inhibition of miR-21 resulted in reduced cell growth and induced apoptosis. Upon AGO2-RIP-Chip, we observed an overall increased enrichment of miR-21 target genes in the IP fraction of miR-21-overexpressing Jurkat cells as compared to the IP fraction of empty vector control cells. We noted a systematic decrease in transcript levels of predicted miR-21 target genes compared to EV control. We identified 72 genes that were 2-fold enriched in the AGO2-IP fraction of miR-21-overexpressing cells that contained a predicted miR-21 binding site. Of these, 71 were enriched 2-fold more in the miR-21-overexpressing cells as compared to EV Jurkat cells. The target gene for which the enrichment was most prominently increased upon miR-21 overexpression was the pro-apoptotic protein LATS1. Luciferase reporter assays confirmed direct targeting of the LATS1 3'UTR by miR-21. In line with the luciferase results, Western blot analysis revealed a decrease in LATS1 upon miR-21 inhibition. LATS1 qRT-PCR analysis in primary T-cells showed that LATS1 levels decrease upon T-cell stimulation while the miR-21 levels increase. Collectively, these data identify the miR-21 target LATS1 as a likely candidate whose inhibition contributes to the anti-apoptotic function of miR-21 in T-cells and perhaps also many types of cancers.
Project description:MiR-21 is an important suppressor of T-cell apoptosis that is also widely overexpressed in many types of cancers. The exact mechanisms related to the anti-apoptotic effect of miR-21 is not well understood. In this study, we applied AGO2 RNA Immunoprecipitation followed by gene expression profiling (RIP-Chip) in Jurkat cells to identify apoptosis-associated miR-21 target genes. We showed that expression of miR-21 rapidly increases upon αCD3/αCD28 activation of Jurkat cells. Inhibition of miR-21 resulted in reduced cell growth and induced apoptosis. Upon AGO2-RIP-Chip, we observed an overall increased enrichment of miR-21 target genes in the IP fraction of miR-21-overexpressing Jurkat cells as compared to the IP fraction of empty vector control cells. We noted a systematic decrease in transcript levels of predicted miR-21 target genes compared to EV control. We identified 72 genes that were 2-fold enriched in the AGO2-IP fraction of miR-21-overexpressing cells that contained a predicted miR-21 binding site. Of these, 71 were enriched 2-fold more in the miR-21-overexpressing cells as compared to EV Jurkat cells. The target gene for which the enrichment was most prominently increased upon miR-21 overexpression was the pro-apoptotic protein LATS1. Luciferase reporter assays confirmed direct targeting of the LATS1 3'UTR by miR-21. In line with the luciferase results, Western blot analysis revealed a decrease in LATS1 upon miR-21 inhibition. LATS1 qRT-PCR analysis in primary T-cells showed that LATS1 levels decrease upon T-cell stimulation while the miR-21 levels increase. Collectively, these data identify the miR-21 target LATS1 as a likely candidate whose inhibition contributes to the anti-apoptotic function of miR-21 in T-cells and perhaps also many types of cancers. Gene expression array on Jurkat cells overexpressing miR-21 and empty vector (EV).
Project description:In order to identify miR-21 targets by a biochemical high-throughput method, we immunopurified RISC Complex and associated mRNAs in both control and miR-21 overexpressing Jurkat cells.
Project description:Mouse Embryonic Stem (ES) cells express a unique set of microRNAs (miRNAs), the miR-290-295 cluster. To elucidate the role of these miRNAs and how they integrate into the ES cell regulatory network requires identification of their direct regulatory targets. The difficulty, however, arises from the limited complementarity of metazoan miRNAs to their targets, with the interaction requiring as few as six nucleotides of the miRNA seed sequence. To identify miR-294 targets, we used Dicer1-null ES cells, which lack all endogenous mature miRNAs, and introduced just miR-294 into these ES cells. We then employed two approaches to discover miR-294 targets in mouse ES cells: transcriptome profiling using microarrays, and a biochemical approach to isolate mRNA targets associated with the Argonaute2 (Ago2) protein of the RISC (RNA Induced Silencing Complex) effector, followed by RNA-Sequencing. In the absence of Dicer1, the RISC complexes are largely devoid of mature miRNAs, and should therefore contain only transfected miR-294 and its base-paired targets. Our data suggest that miR-294 may promote pluripotency by regulating a subset of c-Myc target genes, and upregulating pluripotency-associated genes such as Lin28. For RNA-IP experiments, cells were transfected with 300 pmol of miR-294 or cel-239b control miRNA (Dharmacon) and harvested 12-16 hr after transfection for immunoprecipitation. Following RNA-immunoprecipitation of Ago2-myc, RNA from the INPUT (total RNA) and IP were subjected to library preparation and sequenced by SOLiD. There are 10 samples from Dicer1-null mouse ES cells, which are essentially 5 sample pairs of INPUT (A) and its corresponding RNA-IP (B): Ago2-myc transfected with miR-294 (sampe 1), 2 replicates of Ago2-myc-MUT (catalytically inactive) transfected with miR-294 (sample 2 & 5), 2 replicates of Ago2-myc transfected with cel-239b (sample 3 & 4).
Project description:The aim of the study is to identify miRNA specific targets in Hodgkin lymphoma cell lines. By immunoprecipitation (IP) of wild type Ago2, Ago2 associated gene transcripts (ie miRNA targets) are coimmunoprecipitated. In cells transfected with anti-miR-17/20/93/106, the miR-17 seed family specific targets are not coimmunoprecipitated with Ago2. With microarray analysis, signal intensities of probes associated with Ago2 from untransfected and anti-miRNA transfected cells are compared. Gene transcripts that are depleted from the Ago2-IP fraction upon miRNA inhibition (ie miRNA specific targets) are identified.