Project description:A network of gene regulatory factors such as transcription factors and microRNAs establish and maintain the gene expression pattern during hematopoiesis. In this network transcription factors regulate each other and are involved in regulatory loops with microRNAs.The microRNA cluster miR-17-92 is located within the MIR17HG gene and encodes for six mature microRNAs. It is important for hematopoietic differentiation and plays a central role in malignant disease. However, the transcription factors downstream of miR-17-92 are largely elusive and the transcriptional regulation of miR-17-92 is not fully understood. Here we show that miR-17-92 forms a regulatory loop with the transcription factor TAL1. The miR-17-92 cluster inhibits expression of TAL1 and indirectly leads to decreased stability of the TAL1 transcriptional complex. We found that TAL1 and its heterodimerization partner E47 regulate miR-17-92 transcriptionally. Furthermore, miR-17-92 negatively influences erythroid differentiation, a process that depends on gene activation by the TAL1 complex. Our data give example of how transcription factor activity is fine-tuned during normal hematopoiesis. We postulate that disturbance of the regulatory loop between TAL1 and the miR-17-92 cluster could be an important step in cancer development and progression.
Project description:Knockout of the ubiquitously expressed microRNA-17~92 cluster in mice produces a lethal developmental lung defect. We validated the equally widely expressed pro-apoptotic Bim gene as joint target of miR-17~92 cluster members. To study the contribution of miR-17~92:Bim interaction to miR-17~92 overall function, we set up a system of conditional mutagenesis of the Bim 3’UTR. Blocking miR-17~92:Bim interaction early in development phenocopied the lethal lung phenotype of miR-17~92 ablation. Thus, despite hundreds of overall predicted targets vital miRNA functions can be mediated by a single target gene.
Project description:The miR-17-92 microRNA cluster is often activated in cancer cells, but the identity of its targets remains largely elusive. Here we examined the effects of activation of the entire miR-17-92 cluster on global protein expression in neuroblastoma cells. In this dataset we deposit global mRNA expression data obtained form primary neuroblastoma tumour cells. This data was used to demonstrate negative correlation between TGFB target gene expression and expression of the miR-17-92 cluster.
Project description:We have generated a miR-17-92 transgenic allele (termed miR-17-92 Tg) whose expression can be turned on conditionally by Cre recombinase (Xiao et al, Nature Immunology, 9:405-14, 2008). The mice were crossed to CD19-Cre mice to turn on the transgene expression specifically in B cells.
Project description:We have generated a miR-17-92 transgenic allele (termed miR-17-92 Tg) whose expression can be turned on conditionally by Cre recombinase (Xiao et al, Nature Immunology, 9:405-14, 2008). The mice were crossed to CD19-Cre mice to turn on the transgene expression specifically in B cells.