Project description:There is a growing body of evidence about the presence and the activity of the miRISC in the nucleus of mammalian cells. Here, we show by quantitative proteomic analysis that Ago2 interacts with nucleoplasmic Sfpq in a RNA-dependent fashion. By HITS-CLIP and transcriptomic analyses, we demonstrated that Sfpq directly controls the miRNA targeting of a subset of crucial miRNA-target mRNAs when it binds locally. Sfpq modulates miRNA targeting in both nucleoplasm and cytoplasm, indicating a nucleoplasmic imprinting of Sfpq-target mRNAs that influence miRNA targeting in both cellular compartments. Mechanistically, Sfpq binds to a sizeable set of long 3’UTR forming long aggregates to optimize miRNA position/recruitment to selected binding sites, as we show for Lin28A mRNA. These results extend the miRNA-mediated post-transcriptional gene silencing into the nucleoplasm and indicate that an unique Sfpq-dependent post-transcriptional strategy for controlling both nuclear and cytoplasmic gene expression takes place in cells during physio-pathological events.
Project description:There is a growing body of evidence about the presence and the activity of the miRISC in the nucleus of mammalian cells. Here, we show by quantitative proteomic analysis that Ago2 interacts with nucleoplasmic Sfpq in a RNA-dependent fashion. By HITS-CLIP and transcriptomic analyses, we demonstrated that Sfpq directly controls the miRNA targeting of a subset of crucial miRNA-target mRNAs when it binds locally. Sfpq modulates miRNA targeting in both nucleoplasm and cytoplasm, indicating a nucleoplasmic imprinting of Sfpq-target mRNAs that influence miRNA targeting in both cellular compartments. Mechanistically, Sfpq binds to a sizeable set of long 3’UTR forming long aggregates to optimize miRNA position/recruitment to selected binding sites, as we show for Lin28A mRNA. These results extend the miRNA-mediated post-transcriptional gene silencing into the nucleoplasm and indicate that an unique Sfpq-dependent post-transcriptional strategy for controlling both nuclear and cytoplasmic gene expression takes place in cells during physio-pathological events.
Project description:There is a growing body of evidence about the presence and the activity of the miRISC in the nucleus of mammalian cells. Here, we show by quantitative proteomic analysis that Ago2 interacts with nucleoplasmic Sfpq in a RNA-dependent fashion. By HITS-CLIP and transcriptomic analyses, we demonstrated that Sfpq directly controls the miRNA targeting of a subset of crucial miRNA-target mRNAs when it binds locally. Sfpq modulates miRNA targeting in both nucleoplasm and cytoplasm, indicating a nucleoplasmic imprinting of Sfpq-target mRNAs that influence miRNA targeting in both cellular compartments. Mechanistically, Sfpq binds to a sizeable set of long 3’UTR forming long aggregates to optimize miRNA position/recruitment to selected binding sites, as we show for Lin28A mRNA. These results extend the miRNA-mediated post-transcriptional gene silencing into the nucleoplasm and indicate that an unique Sfpq-dependent post-transcriptional strategy for controlling both nuclear and cytoplasmic gene expression takes place in cells during physio-pathological events.
Project description:There is a growing body of evidence about the presence and the activity of the miRISC in the nucleus of mammalian cells. Here, we show by quantitative proteomic analysis that Ago2 interacts with nucleoplasmic Sfpq in a RNA-dependent fashion. By HITS-CLIP and transcriptomic analyses, we demonstrated that Sfpq directly controls the miRNA targeting of a subset of crucial miRNA-target mRNAs when it binds locally. Sfpq modulates miRNA targeting in both nucleoplasm and cytoplasm, indicating a nucleoplasmic imprinting of Sfpq-target mRNAs that influence miRNA targeting in both cellular compartments. Mechanistically, Sfpq binds to a sizeable set of long 3’UTR forming long aggregates to optimize miRNA position/recruitment to selected binding sites, as we show for Lin28A mRNA. These results extend the miRNA-mediated post-transcriptional gene silencing into the nucleoplasm and indicate that an unique Sfpq-dependent post-transcriptional strategy for controlling both nuclear and cytoplasmic gene expression takes place in cells during physio-pathological events.
Project description:microRNAs (miRNAs) act as sequence-specific guides for Argonaute (AGO) proteins, which mediate post-transcriptional silencing of target mRNAs. Despite their importance in many biological processes, rules governing AGO-miRNA targeting are only partially understood. We use a modified AGO HITS-CLIP strategy, termed CLEAR (Covalent Ligation of Endogenous Argonaute-bound RNAs) CLIP that enriches miRNAs ligated to their endogenous mRNA targets. CLEAR-CLIP mapped ~130,000 endogenous miRNA-target interactions in mouse brain and ~40,000 in human hepatoma cells. Motif and structural analysis define expanded pairing rules for over 200 mammalian miRNAs. Most interactions combine seed-based pairing with distinct, miRNA-specific patterns of auxiliary pairing. At some regulatory sites, this specificity confers distinct silencing functions to miRNA family members with shared seed sequences but divergent 3’ ends. This work provides a means for explicit biochemical identification of miRNA sites in vivo, leading to the discovery that miRNA 3’ end pairing is a general determinant of AGO binding specificity.
Project description:microRNAs (miRNAs) act as sequence-specific guides for Argonaute (AGO) proteins, which mediate post-transcriptional silencing of target mRNAs. Despite their importance in many biological processes, rules governing AGO-miRNA targeting are only partially understood. We use a modified AGO HITS-CLIP strategy, termed CLEAR (Covalent Ligation of Endogenous Argonaute-bound RNAs) CLIP that enriches miRNAs ligated to their endogenous mRNA targets. CLEAR-CLIP mapped ~130,000 endogenous miRNA-target interactions in mouse brain and ~40,000 in human hepatoma cells. Motif and structural analysis define expanded pairing rules for over 200 mammalian miRNAs. Most interactions combine seed-based pairing with distinct, miRNA-specific patterns of auxiliary pairing. At some regulatory sites, this specificity confers distinct silencing functions to miRNA family members with shared seed sequences but divergent 3’ ends. This work provides a means for explicit biochemical identification of miRNA sites in vivo, leading to the discovery that miRNA 3’ end pairing is a general determinant of AGO binding specificity.