Project description:To have a global picture of the targets of the miR-15 family, we assessed transcriptome changes, by deep-sequencing, of HeLa cells transfected with 3 members of the miR-15 family (miR-15a, miR-16 or miR-503) or a control miRNA (cel-miR-231). We observed a very extensive overlap between the genes down-regulated by these 3 miRNAs, as expected for miRNAs belonging to the same family. transcriptmic profiles of HeLa cells treated miR-15a, miR-16, miR-503 and control-miR were generated by deep sequencing, using Illumina HiSeq2000.
Project description:To have a global picture of the targets of the miR-15 family, we assessed transcriptome changes, by deep-sequencing, of HeLa cells transfected with 3 members of the miR-15 family (miR-15a, miR-16 or miR-503) or a control miRNA (cel-miR-231). We observed a very extensive overlap between the genes down-regulated by these 3 miRNAs, as expected for miRNAs belonging to the same family.
Project description:While microRNAs (miRs) have been extensively studied in the context of malignancy and tumor progression, their functions in regulating T cell activation are less clear. We found reduced levels of miR-15a/16 at 3-18 h post-T cell receptor (TCR) stimulation, suggesting a role in shaping T cell activation. An inducible miR15a/16 transgenic mouse model was developed to determine how elevating miR-15a/16 levels during early stages of activation would affect T cell proliferation and to identify TCR signaling pathways regulated by this miR pair. Doxycyclin (DOX) induced expression of miR-15a/16 from 0-18 h post-TCR stimulation decreased ex vivo proliferation as well as in vivo antigen-specific proliferation. Bioinformatic and proteomic approaches were combined to identify MEK1 as a target of miR-15a/16. MEK1 targeting by miR-15a/16 was confirmed using miR mimics that decreased MEK1 containing the 3’-UTR target nucleotide sequence (UGCUGCUA) but did not decrease MEK1 containing a mutated control sequence (AAAAAAAA). Phosphorylation of downstream signaling molecules ERK1/2 and Elk1 were decreased with DOX-induced miR-15a/16 expression. In addition to MEK1, ERK1 was subsequently found to be targeted by miR-15a/16, with DOX induced miR-15a/16 reducing total ERK1 levels in T cells. These findings show that TCR stimulation reduces miR-15a/16 levels at early stages of T cell activation to facilitate increased MEK1 and ERK1, and this promotes sustained MEK1-ERK1/2-Elk1 signaling required for optimal proliferation.
Project description:We constructed a genome wide target profile of hsa-miR-503, hsa-miR-103, and hsa-miR-494 by sequencing RNA isolated from Ago2 immunoprecipitations and total RNA samples following transfection of the respective miRNA in mature duplex form Examination of mRNA levels in HeLa cells and Ago2 immunoprecipitations from HeLa cells following miR-503, miR-103, or miR-494 mature duplex or control siRNA transfection
Project description:Gene expression profile following transfection with miR-503, miR-103, or miR-494 mature duplex Examination of mRNA levels in HeLa cells following transfection of miR-503, miR-103, or miR-494 mature duplex, control siRNA against GFP, or mock transfection (lipofectamine 2000 alone)
Project description:Given the tumor suppressing function of miR-15a/16-1 cluster, we studied its role in the germinal center B-cells that give rise to most lymphoid malignancies.
Project description:Global expression profiling of miRNAs in liver tissue of HBV infected HCC and chronic hepatitis B (CHB) with no fibrosis was evaluated. A total of 40 differentially expressed miRNAs were identified in HCC. Top 10 miRNAs are validated in more numbers of HCC tisuues by qRT PCR. Finally six miRNAs (miR-15a, miR-16, miR-21,miR-29b-3p, miR-126, miR-142-3p, miR-193a-5p) showed similar expression pattern in both microarray and qRT PCR
Project description:Global expression profiling of miRNAs in liver tissue of HBV infected HCC and chronic hepatitis B (CHB) with no fibrosis was evaluated. A total of 40 differentially expressed miRNAs were identified in HCC. Top 10 miRNAs are validated in more numbers of HCC tisuues by qRT PCR. Finally six miRNAs (miR-15a, miR-16, miR-21,miR-29b-3p, miR-126, miR-142-3p, miR-193a-5p) showed similar expression pattern in both microarray and qRT PCR Differential expression analysis of microRNAs in HBV infected HCC (n=4) compared to CHB patients with no fibrosis (n=8) as control.
Project description:MicroRNAs (miRNAs) are 20-25 nucleotides (nt) RNAs that are predicted to post-transcriptionally silence expression of >60% of all protein coding genes in mammals. As such, they form an additional layer of gene regulation that controls most if not all biological processes. MiRNAs are generated from primary transcripts containing single or multiple clustered stem-loop structures that are thought to be recognized and cleaved by the DGCR8/DROSHA Microprocessor complex as independent entities. Contrasting this view, we find that the primary miR-15a stem-loop within the bicistronic miR-15a-16-1 cluster is a poor Microprocessor substrate and is consequently not processed on its own, but that the presence of the neighboring primary miR-16-1 stem-loop on the same transcript can compensate for this deficiency in cis. Using a CRISPR/Cas9 screen, we identify SAFB2 (scaffold attachment factor B2) as an essential co-factor in this miR-16-1-assisted primary miR-15 cleavage. Small RNA sequencing further revealed that deletion of Safb1 and 2 genes reduces not only miR-15a levels, but also affects other clustered miRNAs, among them miR-15b, miR-181b and miR-92a. We therefore postulate a model in which SAFB2 enables processing of suboptimal substrates in a subset of clustered pri-miRNA transcripts.