Project description:Argonaute (Ago) proteins interact with various binding partners and play a pivotal role in microRNA (miRNA)-mediated silencing pathways. By utilizing immunoprecipitation followed by mass spectrometry to determine cytoplasmic Ago2 protein complexes in mouse embryonic stem cells (mESCs), we identified a putative RNA-binding protein FAM120A (also known as OSSA/C9ORF10) as an Ago2 interacting protein. Individual nucleotide resolution Cross-Linking and ImmunoPrecipitation (iCLIP) analysis revealed that FAM120A binds to homopolymeric tracts in 3´ UTRs of about 2,000 mRNAs, particularly poly(G) sequences. Comparison of FAM120A iCLIP and Ago2 iCLIP reveals that greater than one-third of mRNAs bound by Ago2 in mESCs are co-bound by FAM120A. Furthermore, such FAM120A-bound Ago2 target genes are not subject to Ago2-mediated target degradation. Reporter assays suggest that the 3´ UTRs of several FAM120A-bound miRNA target genes are less sensitive to Ago2-mediated target repression than those of FAM120A-unbound miRNA targets and FAM120A modulates them via its G-rich target sites. These findings suggest that Ago2 may exist in multiple protein complexes with varying degrees of functionality.
Project description:Argonaute (Ago) proteins interact with various binding partners and play a pivotal role in microRNA (miRNA)-mediated silencing pathways. By utilizing immunoprecipitation followed by mass spectrometry to determine cytoplasmic Ago2 protein complexes in mouse embryonic stem cells (mESCs), we identified a putative RNA-binding protein FAM120A (also known as OSSA/C9ORF10) as an Ago2 interacting protein. Individual nucleotide resolution cross-linking and immunoprecipitation (iCLIP) analysis revealed that FAM120A binds to homopolymeric tracts in 3'-UTRs of about 2000 mRNAs, particularly poly(G) sequences. Comparison of FAM120A iCLIP and Ago2 iCLIP reveals that greater than one-third of mRNAs bound by Ago2 in mESCs are co-bound by FAM120A. Furthermore, such FAM120A-bound Ago2 target genes are not subject to Ago2-mediated target degradation. Reporter assays suggest that the 3'-UTRs of several FAM120A-bound miRNA target genes are less sensitive to Ago2-mediated target repression than those of FAM120A-unbound miRNA targets and FAM120A modulates them via its G-rich target sites. These findings suggest that Ago2 may exist in multiple protein complexes with varying degrees of functionality.
Project description:Ago2 binds mature microRNAs (miRNAs) to regulate gene expression. A mutant Ago2 is constructed to render it unable to bind miRNAs and inhibit mRNA translation.
Project description:Ago2 binds mature microRNAs (miRNAs) to regulate gene expression. A mutant Ago2 is constructed to render it unable to bind miRNAs and inhibit mRNA translation. Human 293T cells were transiently transfected with a plasmid that encoded a FLAG-tagged wildtype human Ago2 or mutant Ago2. FLAG IP was preformed, and assoicated RNA was isolated and subjected miRNA microarray analysis.
Project description:To illuminate the molecular mechanisms driving neuronal differentiation we generated a mouse line amenable to mapping miRNA-target interactions in rare cell types. Biochemical approaches to purify AGO2-miRNA-target complexes have successfully mapped MTIs in abundant populations of neurons. However, due to their technical complexity and high background, these approaches are not suitable for mapping interactions in rare cell populations such the many neuronal subtypes that compose the mammalian brain. We therefore generated a mouse line with a conditional SpyTag3, which is small and offers near-infinite affinity for pull-downs, in the endogenous Ago2 gene. We then developed a method Spy3-AGO2 pull-down and sequencing (SAPseq), which we have used to accurately map miRNA-target interactions in developing Purkinje cells, a rare population of cells in the cerebellum.
Project description:We deciphered Ago2:RNA interactions in post-mortem human heart tissues using crosslinking immunoprecipitation coupled with high-throughput sequencing (HITS-CLIP) to generate the first transcriptome-wide map of miR targeting events in human myocardium, detecting 4000 cardiac Ago2 binding sites across >2200 target transcripts.
Project description:To illuminate the molecular mechanisms driving neuronal differentiation we generated a mouse line amenable to mapping miRNA-target interactions in rare cell types. Biochemical approaches to purify AGO2-miRNA-target complexes have successfully mapped MTIs in abundant populations of neurons. However, due to their technical complexity and high background, these approaches are not suitable for mapping interactions in rare cell populations such the many neuronal subtypes that compose the mammalian brain. We therefore generated a mouse line with a conditional SpyTag3, which is small and offers near-infinite affinity for pull-downs, in the endogenous Ago2 gene. We then developed a method Spy3-AGO2 pull-down and sequencing (SAPseq), which we first benchmarked for in vivo use using cortical pyramidal neurons, an abundant population.
Project description:Here, seeking to gain insight into the array of transcripts engaged with miRNAs in human brain, we performed HITS-CLIP to profile transcriptome-wide Ago2:RNA interactions in a panel of eleven post-mortem adult human brain samples harvested from adult motor cortex and cingulate gyrus, regions associated with movement and psychiatric disorders . High-throughput sequencing of RNA isolated by crosslinking immunoprecipitation (HITS-CLIP) Eleven post-mortem adult human brain tissues were subjected to ultraviolet radiation to crosslink proteins with nucleic acids, and HITS-CLIP was performed as previously described by Chi et al Nature. 2009 Jul 23;460(7254):479-86 using an anti-Ago2 polyclonal antibody and some additional modifications.
Project description:We deciphered Ago2:RNA interactions in post-mortem human heart tissues using crosslinking immunoprecipitation coupled with high-throughput sequencing (HITS-CLIP) to generate the first transcriptome-wide map of miR targeting events in human myocardium, detecting 4000 cardiac Ago2 binding sites across >2200 target transcripts. Profiling AGO2-associated RNAs in cardiac tissues obtained from 6 donors with heart diseases of differing etiologies
Project description:Here, seeking to gain insight into the array of transcripts engaged with miRNAs in human brain, we performed HITS-CLIP to profile transcriptome-wide Ago2:RNA interactions in a panel of eleven post-mortem adult human brain samples harvested from adult motor cortex and cingulate gyrus, regions associated with movement and psychiatric disorders .