Project description:The goal of this study is to understand how IMP2 contributes to T2D traits by regulating pancreatic beta cell growth and function. Islets from control and Rip2;IMP2 mice were generated by deep sequencing. In additon, we also perfomred IMP2 RIP-Seq to identify IMP2 targets.
Project description:RNA-based regulatory mechanisms play important roles in the development and plasticity of neural circuits and neurologic disease. Developing axons provide a well suited model to study RNA-based regulation, and contain specific subsets of mRNAs that are locally translated and have roles in axon pathfinding. However, the RNA-binding proteins involved in axon pathfinding, and their corresponding mRNA targets, are still largely unknown. Here we find that the RNA-binding protein IMP2 (Igf2bp2) is strikingly enriched in developing axon tracts, including in spinal commissural axons. We used the HITS-CLIP approach to perform a genome-wide identification of RNAs that interact directly with IMP2 in the native context of developing brain. This IMP2 interactome was highly enriched for mRNA targets related to axon guidance. Accordingly, IMP2 knockdown in the developing spinal cord led to strong defects in commissural axon trajectories at the midline intermediate target. These results reveal a highly distinctive axonal enrichment of IMP2, show that it interacts with a network of axon guidance-related mRNAs, and reveal its requirement for normal axon pathfinding during vertebrate development. CLIP-seq
Project description:Using IMP2-deficient mice to study the role of the RNA-binding protein (RBP) IMP2 in models of autoimmunity, namely autoimmune glomerulonephritis
Project description:RNA-based regulatory mechanisms play important roles in the development and plasticity of neural circuits and neurologic disease. Developing axons provide a well suited model to study RNA-based regulation, and contain specific subsets of mRNAs that are locally translated and have roles in axon pathfinding. However, the RNA-binding proteins involved in axon pathfinding, and their corresponding mRNA targets, are still largely unknown. Here we find that the RNA-binding protein IMP2 (Igf2bp2) is strikingly enriched in developing axon tracts, including in spinal commissural axons. We used the HITS-CLIP approach to perform a genome-wide identification of RNAs that interact directly with IMP2 in the native context of developing brain. This IMP2 interactome was highly enriched for mRNA targets related to axon guidance. Accordingly, IMP2 knockdown in the developing spinal cord led to strong defects in commissural axon trajectories at the midline intermediate target. These results reveal a highly distinctive axonal enrichment of IMP2, show that it interacts with a network of axon guidance-related mRNAs, and reveal its requirement for normal axon pathfinding during vertebrate development.
Project description:Data showing the late 2-cell-stage, control embryos (Imp2♀+/♂+) and Imp2-knockout embryos (Imp2♀−/♂+) for HPLC MS/MS analysis. 3 replicates were performed using 330 embryos per group.
Project description:Cancer stem cells (CSC) dictate tumor cell heterogeneity in diverse cancer types and arise, in part, from microRNA (miRNA)-dependent alteration of gene expression. The let-7 miRNA family induces differentiation by silencing genes that maintain stemness and is repressed by the RNA-binding proteins LIN28A/B, which preserve stemness in normal embryonic and malignant cells. Here, we observed that LIN28A/B is undetectable in glioma stem cells (GSC) whereas let-7 and, paradoxically, their target genes are highly expressed. Using photoactivatable-ribonucloside-enchanced crosslinking and immunoprecipitation (PAR-CLIP), we show that insulin-like growth factor-2 mRNA-binding protein 2 (IMP2) protects let-7 target genes from silencing and provides a mechanistically distinct alternative to LIN28A/B toward both GSC and neural stem cell specification. Our observations define the RNA-binding repertoire of IMP2 and identify a mechanism by which it supports GSC maintenance.
Project description:Different from most publication to date, in this study we find IMP1 and IMP2, two closely related RNA binding proteins, have different clients in MEF cells
Project description:The Igf2 mRNA binding protein2/Imp2 was selectively deleted from adult mouse muscle; two phenotypes were observed: modestly decreased accrual of skeletal muscle mass after weaning and reduced wheel running activity but normal forced treadmill performance. Reduced voluntary activity occurs when fed a high fat diet but is normalized when consuming standard chow. The reduced muscle mass is due to diminished autocrine Igf2 production, reduced Akt1 activation, disinhibition of Gsk3α and reduced protein synthesis, without altered mTOR complex1 activity. The diet-dependent reduction in spontaneous exercise is accompanied by suboptimal muscle fatty acid oxidation, caused by reduced PPARα mRNA and protein, the former an Imp2 client. Nevertheless, in contrast to global Imp2 deficiency, muscle specific Imp2 inactivation does not alter glucose tolerance or the hypoglycemic effect of insulin. Imp2 deficiency in skeletal muscle reduces autocrine production of Igf2 and fiber growth and disorders nutrient metabolism so as to reduce voluntary physical activity.
