1
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Mohamed AA, Wang PY, Bartel DP, Vos SM. The structural basis for RNA slicing by human Argonaute2. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.19.608718. [PMID: 39229170 PMCID: PMC11370433 DOI: 10.1101/2024.08.19.608718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2024]
Abstract
Argonaute (AGO) proteins associate with guide RNAs to form complexes that slice transcripts that pair to the guide. This slicing drives post-transcriptional gene-silencing pathways that are essential for many eukaryotes and the basis for new clinical therapies. Despite this importance, structural information on eukaryotic AGOs in a fully paired, slicing-competent conformation-hypothesized to be intrinsically unstable-has been lacking. Here we present the cryogenic-electron microscopy structure of a human AGO-guide complex bound to a fully paired target, revealing structural rearrangements that enable this conformation. Critically, the N domain of AGO rotates to allow the RNA full access to the central channel and forms contacts that license rapid slicing. Moreover, a conserved loop in the PIWI domain secures the RNA near the active site to enhance slicing rate and specificity. These results explain how AGO accommodates targets possessing the pairing specificity typically observed in biological and clinical slicing substrates.
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Affiliation(s)
- Abdallah A Mohamed
- Department of Biology, Massachusetts Institute of Technology, 31 Ames Street, Cambridge, MA, 02139, USA
- These authors contributed equally
| | - Peter Y Wang
- Department of Biology, Massachusetts Institute of Technology, 31 Ames Street, Cambridge, MA, 02139, USA
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA, 02142, USA
- Howard Hughes Medical Institute, Cambridge, MA, 02142, USA
- These authors contributed equally
| | - David P Bartel
- Department of Biology, Massachusetts Institute of Technology, 31 Ames Street, Cambridge, MA, 02139, USA
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA, 02142, USA
- Howard Hughes Medical Institute, Cambridge, MA, 02142, USA
| | - Seychelle M Vos
- Department of Biology, Massachusetts Institute of Technology, 31 Ames Street, Cambridge, MA, 02139, USA
- Howard Hughes Medical Institute, Cambridge, MA, 02142, USA
- Lead contact
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2
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Wang PY, Bartel DP. The guide-RNA sequence dictates the slicing kinetics and conformational dynamics of the Argonaute silencing complex. Mol Cell 2024; 84:2918-2934.e11. [PMID: 39025072 PMCID: PMC11371465 DOI: 10.1016/j.molcel.2024.06.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 05/03/2024] [Accepted: 06/24/2024] [Indexed: 07/20/2024]
Abstract
The RNA-induced silencing complex (RISC), which powers RNA interference (RNAi), consists of a guide RNA and an Argonaute protein that slices target RNAs complementary to the guide. We find that, for different guide-RNA sequences, slicing rates of perfectly complementary bound targets can be surprisingly different (>250-fold range), and that faster slicing confers better knockdown in cells. Nucleotide sequence identities at guide-RNA positions 7, 10, and 17 underlie much of this variation in slicing rates. Analysis of one of these determinants implicates a structural distortion at guide nucleotides 6-7 in promoting slicing. Moreover, slicing directed by different guide sequences has an unanticipated, 600-fold range in 3'-mismatch tolerance, attributable to guides with weak (AU-rich) central pairing requiring extensive 3' complementarity (pairing beyond position 16) to more fully populate the slicing-competent conformation. Together, our analyses identify sequence determinants of RISC activity and provide biochemical and conformational rationale for their action.
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Affiliation(s)
- Peter Y Wang
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - David P Bartel
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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3
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Wang PY, Bartel DP. The guide RNA sequence dictates the slicing kinetics and conformational dynamics of the Argonaute silencing complex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.15.562437. [PMID: 38766062 PMCID: PMC11100590 DOI: 10.1101/2023.10.15.562437] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
The RNA-induced silencing complex (RISC), which powers RNA interference (RNAi), consists of a guide RNA and an Argonaute protein that slices target RNAs complementary to the guide. We find that for different guide-RNA sequences, slicing rates of perfectly complementary, bound targets can be surprisingly different (>250-fold range), and that faster slicing confers better knockdown in cells. Nucleotide sequence identities at guide-RNA positions 7, 10, and 17 underlie much of this variation in slicing rates. Analysis of one of these determinants implicates a structural distortion at guide nucleotides 6-7 in promoting slicing. Moreover, slicing directed by different guide sequences has an unanticipated, 600-fold range in 3'-mismatch tolerance, attributable to guides with weak (AU-rich) central pairing requiring extensive 3' complementarity (pairing beyond position 16) to more fully populate the slicing-competent conformation. Together, our analyses identify sequence determinants of RISC activity and provide biochemical and conformational rationale for their action.
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Affiliation(s)
- Peter Y. Wang
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA, 02142, USA
- Howard Hughes Medical Institute, Cambridge, MA, 02142, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - David P. Bartel
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA, 02142, USA
- Howard Hughes Medical Institute, Cambridge, MA, 02142, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Lead contact
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4
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Zheng L, Zhou B, Yang Y, Zan B, Zhong B, Wu B, Feng Y, Liu Q, Hong L. Mn 2+-induced structural flexibility enhances the entire catalytic cycle and the cleavage of mismatches in prokaryotic argonaute proteins. Chem Sci 2024; 15:5612-5626. [PMID: 38638240 PMCID: PMC11023060 DOI: 10.1039/d3sc06221j] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 03/01/2024] [Indexed: 04/20/2024] Open
Abstract
Prokaryotic Argonaute (pAgo) proteins, a class of DNA/RNA-guided programmable endonucleases, have been extensively utilized in nucleic acid-based biosensors. The specific binding and cleavage of nucleic acids by pAgo proteins, which are crucial processes for their applications, are dependent on the presence of Mn2+ bound in the pockets, as verified through X-ray crystallography. However, a comprehensive understanding of how dissociated Mn2+ in the solvent affects the catalytic cycle, and its underlying regulatory role in this structure-function relationship, remains underdetermined. By combining experimental and computational methods, this study reveals that unbound Mn2+ in solution enhances the flexibility of diverse pAgo proteins. This increase in flexibility through decreasing the number of hydrogen bonds, induced by Mn2+, leads to higher affinity for substrates, thus facilitating cleavage. More importantly, Mn2+-induced structural flexibility increases the mismatch tolerance between guide-target pairs by increasing the conformational states, thereby enhancing the cleavage of mismatches. Further simulations indicate that the enhanced flexibility in linkers triggers conformational changes in the PAZ domain for recognizing various lengths of nucleic acids. Additionally, Mn2+-induced dynamic alterations of the protein cause a conformational shift in the N domain and catalytic sites towards their functional form, resulting in a decreased energy penalty for target release and cleavage. These findings demonstrate that the dynamic conformations of pAgo proteins, resulting from the presence of the unbound Mn2+ in solution, significantly promote the catalytic cycle of endonucleases and the tolerance of cleavage to mismatches. This flexibility enhancement mechanism serves as a general strategy employed by Ago proteins from diverse prokaryotes to accomplish their catalytic functions and provide useful information for Ago-based precise molecular diagnostics.
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Affiliation(s)
- Lirong Zheng
- Institute of Natural Sciences, Shanghai Jiao Tong University Shanghai 200240 China
- Department of Cell and Developmental Biology & Michigan Neuroscience Institute, University of Michigan Medical School 48105 Ann Arbor MI USA
| | - Bingxin Zhou
- Institute of Natural Sciences, Shanghai Jiao Tong University Shanghai 200240 China
- Shanghai National Center for Applied Mathematics (SJTU Center), Shanghai Jiao Tong University Shanghai 200240 China
| | - Yu Yang
- State Key Laboratory for Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University Shanghai 200240 China
| | - Bing Zan
- Institute of Natural Sciences, Shanghai Jiao Tong University Shanghai 200240 China
| | - Bozitao Zhong
- State Key Laboratory for Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University Shanghai 200240 China
| | - Banghao Wu
- State Key Laboratory for Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University Shanghai 200240 China
| | - Yan Feng
- State Key Laboratory for Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University Shanghai 200240 China
| | - Qian Liu
- State Key Laboratory for Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University Shanghai 200240 China
| | - Liang Hong
- Institute of Natural Sciences, Shanghai Jiao Tong University Shanghai 200240 China
- State Key Laboratory for Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University Shanghai 200240 China
- Shanghai National Center for Applied Mathematics (SJTU Center), Shanghai Jiao Tong University Shanghai 200240 China
- Zhangjiang Institute for Advanced Study, Shanghai Jiao Tong University Shanghai 200240 China
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5
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Buhagiar AF, Kleaveland B. To kill a microRNA: emerging concepts in target-directed microRNA degradation. Nucleic Acids Res 2024; 52:1558-1574. [PMID: 38224449 PMCID: PMC10899785 DOI: 10.1093/nar/gkae003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 12/21/2023] [Accepted: 01/02/2024] [Indexed: 01/16/2024] Open
Abstract
MicroRNAs (miRNAs) guide Argonaute (AGO) proteins to bind mRNA targets. Although most targets are destabilized by miRNA-AGO binding, some targets induce degradation of the miRNA instead. These special targets are also referred to as trigger RNAs. All triggers identified thus far have binding sites with greater complementarity to the miRNA than typical target sites. Target-directed miRNA degradation (TDMD) occurs when trigger RNAs bind the miRNA-AGO complex and recruit the ZSWIM8 E3 ubiquitin ligase, leading to AGO ubiquitination and proteolysis and subsequent miRNA destruction. More than 100 different miRNAs are regulated by ZSWIM8 in bilaterian animals, and hundreds of trigger RNAs have been predicted computationally. Disruption of individual trigger RNAs or ZSWIM8 has uncovered important developmental and physiologic roles for TDMD across a variety of model organisms and cell types. In this review, we highlight recent progress in understanding the mechanistic basis and functions of TDMD, describe common features of trigger RNAs, outline best practices for validating trigger RNAs, and discuss outstanding questions in the field.
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Affiliation(s)
- Amber F Buhagiar
- Department of Pathology and Lab Medicine, Weill Cornell Medicine, New York, NY10065, USA
| | - Benjamin Kleaveland
- Department of Pathology and Lab Medicine, Weill Cornell Medicine, New York, NY10065, USA
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6
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Porcelli F, Casavola AR, Grottesi A, Schiumarini D, Avaldi L. Probing the conformational dynamics of an Ago-RNA complex in water/methanol solution. Phys Chem Chem Phys 2024; 26:2497-2508. [PMID: 38170800 DOI: 10.1039/d3cp05530b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Argonaute (Ago) proteins mediate target recognition guiding miRNA to bind complementary mRNA primarily in the seed region. However, additional pairing can occur beyond the seed, forming a supplementary duplex that can contribute to the guide-target affinity. In order to shed light on the connection, between protein-RNA interactions and miRNA-mRNA seed and supplementary duplex mobility, we carried out molecular dynamics simulations at the microsecond time-scale using a different approach compared to the ones normally used. Until now, theoretical investigations with classical MD on Ago-RNA complexes have been focused primarily on pure water solvent, which mimics the natural environment of biological molecules. Here, we explored the conformational space of a human Ago2 (hAgo2) bound to the seed + supplementary miRNA-mRNA duplex, using the solvent environment as a molecular probe. MD simulations have been performed in a mixture of water/MeOH at a molar ratio of 70 : 30 as well as in pure water for comparison. Our findings revealed that the mixed solvent promotes protein RNA association, principally enhancing salt-linkages between basic amino acid side-chains and acidic phosphates of the sugar-phosphate backbone. The primary effect registered was the restriction of supplementary duplex flexibility and the stabilization of the miRNA 3' terminus. Interestingly, we observed that the influence of the solvent appears to have almost no impact on the conformation of the seed duplex.
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Affiliation(s)
- Francesco Porcelli
- CNR-Istituto di Struttura della Materia, Area della Ricerca di Roma 1, CP 10 Monterotondo Scalo, Italy.
| | - Anna Rita Casavola
- CNR-Istituto di Struttura della Materia, Area della Ricerca di Roma 1, CP 10 Monterotondo Scalo, Italy.
| | | | - Donatella Schiumarini
- CNR-Istituto di Struttura della Materia, Area della Ricerca di Roma 1, CP 10 Monterotondo Scalo, Italy.
| | - Lorenzo Avaldi
- CNR-Istituto di Struttura della Materia, Area della Ricerca di Roma 1, CP 10 Monterotondo Scalo, Italy.
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7
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Kish M, Ivory DP, Phillips JJ. Transient Structural Dynamics of Glycogen Phosphorylase from Nonequilibrium Hydrogen/Deuterium-Exchange Mass Spectrometry. J Am Chem Soc 2024; 146:298-307. [PMID: 38158228 PMCID: PMC10786028 DOI: 10.1021/jacs.3c08934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 12/12/2023] [Accepted: 12/13/2023] [Indexed: 01/03/2024]
Abstract
It remains a major challenge to ascertain the specific structurally dynamic changes that underpin protein functional switching. There is a growing need in molecular biology and drug discovery to complement structural models with the ability to determine the dynamic structural changes that occur as these proteins are regulated and function. The archetypal allosteric enzyme glycogen phosphorylase is a clinical target of great interest to treat type II diabetes and metastatic cancers. Here, we developed a time-resolved nonequilibrium millisecond hydrogen/deuterium-exchange mass spectrometry (HDX-MS) approach capable of precisely locating dynamic structural changes during allosteric activation and inhibition of glycogen phosphorylase. We resolved obligate transient changes in the localized structure that are absent when directly comparing active/inactive states of the enzyme and show that they are common to allosteric activation by AMP and inhibition by caffeine, operating at different sites. This indicates that opposing allosteric regulation by inhibitor and activator ligands is mediated by pathways that intersect with a common structurally dynamic motif. This mass spectrometry approach uniquely stands to discover local transient structural dynamics and could be used broadly to identify features that influence the structural transitions of proteins.
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Affiliation(s)
- Monika Kish
- Living
Systems Institute, Department of Biosciences, University of Exeter, Stocker Road, Exeter EX4
4QD, U.K.
| | - Dylan P. Ivory
- Living
Systems Institute, Department of Biosciences, University of Exeter, Stocker Road, Exeter EX4
4QD, U.K.
| | - Jonathan J. Phillips
- Living
Systems Institute, Department of Biosciences, University of Exeter, Stocker Road, Exeter EX4
4QD, U.K.
- Alan
Turing Institute, British Library, London NW1 2DB, U.K.
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8
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Bofill-De Ros X, Vang Ørom UA. Recent progress in miRNA biogenesis and decay. RNA Biol 2024; 21:1-8. [PMID: 38031325 PMCID: PMC10761092 DOI: 10.1080/15476286.2023.2288741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/17/2023] [Indexed: 12/01/2023] Open
Abstract
MicroRNAs are a class of small regulatory RNAs that mediate regulation of protein synthesis by recognizing sequence elements in mRNAs. MicroRNAs are processed through a series of steps starting from transcription and primary processing in the nucleus to precursor processing and mature function in the cytoplasm. It is also in the cytoplasm where levels of mature microRNAs can be modulated through decay mechanisms. Here, we review the recent progress in the lifetime of a microRNA at all steps required for maintaining their homoeostasis. The increasing knowledge about microRNA regulation upholds great promise as therapeutic targets.
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Affiliation(s)
- Xavier Bofill-De Ros
- RNA Biology and Innovation, Institute of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
- RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, USA
| | - Ulf Andersson Vang Ørom
- RNA Biology and Innovation, Institute of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
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9
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Shang R, Lee S, Senavirathne G, Lai EC. microRNAs in action: biogenesis, function and regulation. Nat Rev Genet 2023; 24:816-833. [PMID: 37380761 PMCID: PMC11087887 DOI: 10.1038/s41576-023-00611-y] [Citation(s) in RCA: 81] [Impact Index Per Article: 81.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/27/2023] [Indexed: 06/30/2023]
Abstract
Ever since microRNAs (miRNAs) were first recognized as an extensive gene family >20 years ago, a broad community of researchers was drawn to investigate the universe of small regulatory RNAs. Although core features of miRNA biogenesis and function were revealed early on, recent years continue to uncover fundamental information on the structural and molecular dynamics of core miRNA machinery, how miRNA substrates and targets are selected from the transcriptome, new avenues for multilevel regulation of miRNA biogenesis and mechanisms for miRNA turnover. Many of these latest insights were enabled by recent technological advances, including massively parallel assays, cryogenic electron microscopy, single-molecule imaging and CRISPR-Cas9 screening. Here, we summarize the current understanding of miRNA biogenesis, function and regulation, and outline challenges to address in the future.
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Affiliation(s)
- Renfu Shang
- Developmental Biology Program, Sloan Kettering Institute, New York, NY, USA
| | - Seungjae Lee
- Developmental Biology Program, Sloan Kettering Institute, New York, NY, USA
| | - Gayan Senavirathne
- Developmental Biology Program, Sloan Kettering Institute, New York, NY, USA
| | - Eric C Lai
- Developmental Biology Program, Sloan Kettering Institute, New York, NY, USA.
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10
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Kosek DM, Banijamali E, Becker W, Petzold K, Andersson E. Efficient 3'-pairing renders microRNA targeting less sensitive to mRNA seed accessibility. Nucleic Acids Res 2023; 51:11162-11177. [PMID: 37819016 PMCID: PMC10639062 DOI: 10.1093/nar/gkad795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 09/15/2023] [Accepted: 09/19/2023] [Indexed: 10/13/2023] Open
Abstract
MicroRNAs (miRNAs) are short RNAs that post-transcriptionally regulate gene expression by binding to specific sites in mRNAs. Site recognition is primarily mediated by the seed region (nucleotides g2-g8 in the miRNA), but pairing beyond the seed (3'-pairing) is important for some miRNA:target interactions. Here, we use SHAPE, luciferase reporter assays and transcriptomics analyses to study the combined effect of 3'-pairing and secondary structures in mRNAs on repression efficiency. Using the interaction between miR-34a and its SIRT1 binding site as a model, we provide structural and functional evidence that 3'-pairing can compensate for low seed-binding site accessibility, enabling repression of sites that would otherwise be ineffective. We show that miRNA 3'-pairing regions can productively base-pair with nucleotides far upstream of the seed-binding site and that both hairpins and unstructured bulges within the target site are tolerated. We use SHAPE to show that sequences that overcome inaccessible seed-binding sites by strong 3'-pairing adopt the predicted structures and corroborate the model using luciferase assays and high-throughput modelling of 8177 3'-UTR targets for six miRNAs. Finally, we demonstrate that PHB2, a target of miR-141, is an inaccessible target rescued by efficient 3'-pairing. We propose that these results could refine predictions of effective target sites.
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Affiliation(s)
- David M Kosek
- Department of Cell and Molecular Biology, Karolinska Institute, Biomedicum 9B, Solnavägen 9, 17177Stockholm, Sweden
| | - Elnaz Banijamali
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Biomedicum 9B, Solnavägen 9, 17177Stockholm, Sweden
| | - Walter Becker
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Biomedicum 9B, Solnavägen 9, 17177Stockholm, Sweden
| | - Katja Petzold
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Biomedicum 9B, Solnavägen 9, 17177Stockholm, Sweden
- Department of Medical Biochemistry and Microbiology, Uppsala University, Biomedical Centre D9:3, Husargatan 3, 752 37 Uppsala, Sweden
| | - Emma R Andersson
- Department of Cell and Molecular Biology, Karolinska Institute, Biomedicum 9B, Solnavägen 9, 17177Stockholm, Sweden
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11
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Larivera S, Neumeier J, Meister G. Post-transcriptional gene silencing in a dynamic RNP world. Biol Chem 2023; 404:1051-1067. [PMID: 37739934 DOI: 10.1515/hsz-2023-0203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 08/04/2023] [Indexed: 09/24/2023]
Abstract
MicroRNA (miRNA)-guided gene silencing is a key regulatory process in various organisms and linked to many human diseases. MiRNAs are processed from precursor molecules and associate with Argonaute proteins to repress the expression of complementary target mRNAs. Excellent work by numerous labs has contributed to a detailed understanding of the mechanisms of miRNA function. However, miRNA effects have mostly been analyzed and viewed as isolated events and their natural environment as part of complex RNA-protein particles (RNPs) is often neglected. RNA binding proteins (RBPs) regulate key enzymes of the miRNA processing machinery and furthermore RBPs or readers of RNA modifications may modulate miRNA activity on mRNAs. Such proteins may function similarly to miRNAs and add their own contributions to the overall expression level of a particular gene. Therefore, post-transcriptional gene regulation might be more the sum of individual regulatory events and should be viewed as part of a dynamic and complex RNP world.
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Affiliation(s)
- Simone Larivera
- Regensburg Center for Biochemistry (RCB), Laboratory for RNA Biology, University of Regensburg, D-93053, Regensburg, Germany
| | - Julia Neumeier
- Regensburg Center for Biochemistry (RCB), Laboratory for RNA Biology, University of Regensburg, D-93053, Regensburg, Germany
| | - Gunter Meister
- Regensburg Center for Biochemistry (RCB), Laboratory for RNA Biology, University of Regensburg, D-93053, Regensburg, Germany
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12
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Duran E, Schmidt A, Welty R, Jalihal AP, Pitchiaya S, Walter NG. Utilizing functional cell-free extracts to dissect ribonucleoprotein complex biology at single-molecule resolution. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1787. [PMID: 37042458 PMCID: PMC10524090 DOI: 10.1002/wrna.1787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Revised: 03/06/2023] [Accepted: 03/21/2023] [Indexed: 04/13/2023]
Abstract
Cellular machineries that drive and regulate gene expression often rely on the coordinated assembly and interaction of a multitude of proteins and RNA together called ribonucleoprotein complexes (RNPs). As such, it is challenging to fully reconstitute these cellular machines recombinantly and gain mechanistic understanding of how they operate and are regulated within the complex environment that is the cell. One strategy for overcoming this challenge is to perform single molecule fluorescence microscopy studies within crude or recombinantly supplemented cell extracts. This strategy enables elucidation of the interaction and kinetic behavior of specific fluorescently labeled biomolecules within RNPs under conditions that approximate native cellular environments. In this review, we describe single molecule fluorescence microcopy approaches that dissect RNP-driven processes within cellular extracts, highlighting general strategies used in these methods. We further survey biological advances in the areas of pre-mRNA splicing and transcription regulation that have been facilitated through this approach. Finally, we conclude with a summary of practical considerations for the implementation of the featured approaches to facilitate their broader future implementation in dissecting the mechanisms of RNP-driven cellular processes. This article is categorized under: RNA Structure and Dynamics > RNA Structure, Dynamics and Chemistry RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems.
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Affiliation(s)
- Elizabeth Duran
- Single Molecule Analysis Group, Department of Chemistry, University of Michigan, Ann Arbor, Michigan, USA
| | - Andreas Schmidt
- Single Molecule Analysis Group, Department of Chemistry, University of Michigan, Ann Arbor, Michigan, USA
| | - Robb Welty
- Single Molecule Analysis Group, Department of Chemistry, University of Michigan, Ann Arbor, Michigan, USA
| | - Ameya P Jalihal
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Sethuramasundaram Pitchiaya
- Michigan Center for Translational Pathology, Department of Pathology, Department of Urology, Michigan Medicine, Ann Arbor, Michigan, USA
| | - Nils G Walter
- Single Molecule Analysis Group, Department of Chemistry, University of Michigan, Ann Arbor, Michigan, USA
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13
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Bressendorff S, Kausika S, Sjøgaard IMZ, Oksbjerg ED, Michels A, Poulsen C, Brodersen P. The N-coil and the globular N-terminal domain of plant ARGONAUTE1 are interaction hubs for regulatory factors. Biochem J 2023; 480:957-974. [PMID: 37278687 DOI: 10.1042/bcj20230025] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 06/06/2023] [Accepted: 06/06/2023] [Indexed: 06/07/2023]
Abstract
The effector complex of RNA interference (RNAi) contains at its core an ARGONAUTE (AGO) protein bound to a small guide RNA. AGO proteins adopt a two-lobed structure in which the N-terminal (N) and Piwi-Argonaute-Zwille (PAZ) domains make up one lobe, while the middle (MID) and Piwi domains make up the other. Specific biochemical functions of PAZ, MID and Piwi domains of eukaryotic AGO proteins have been described, but the functions of the N domain remain less clear. Here, we use yeast two-hybrid screening with the N domain of the founding member of the AGO protein family, Arabidopsis AGO1, to reveal that it interacts with many factors involved in regulated proteolysis. Interaction with a large group of proteins, including the autophagy cargo receptors ATI1 and ATI2, requires residues in a short, linear region, the N-coil, that joins the MID-Piwi lobe in the three-dimensional structure of AGO. In contrast, the F-box protein AUF1 interacts with AGO1 independently of the N-coil and requires distinct residues in the globular N domain itself. Mutation of AGO1 residues necessary for interaction with protein degradation factors in yeast stabilizes reporters fused to the AGO1 N domain in plants, supporting their in vivo relevance. Our results define distinct regions of the N domain implicated in protein-protein interaction, and point to a particular importance of the AGO1 N-coil as a site of interaction with regulatory factors.
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Affiliation(s)
- Simon Bressendorff
- Copenhagen Plant Science Center, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Swathi Kausika
- Copenhagen Plant Science Center, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Ida Marie Zobbe Sjøgaard
- Copenhagen Plant Science Center, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Emilie Duus Oksbjerg
- Copenhagen Plant Science Center, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Alec Michels
- Copenhagen Plant Science Center, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Christian Poulsen
- Copenhagen Plant Science Center, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Peter Brodersen
- Copenhagen Plant Science Center, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark
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Nam K, Wolf-Watz M. Protein dynamics: The future is bright and complicated! STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2023; 10:014301. [PMID: 36865927 PMCID: PMC9974214 DOI: 10.1063/4.0000179] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 02/03/2023] [Indexed: 06/18/2023]
Abstract
Biological life depends on motion, and this manifests itself in proteins that display motion over a formidable range of time scales spanning from femtoseconds vibrations of atoms at enzymatic transition states, all the way to slow domain motions occurring on micro to milliseconds. An outstanding challenge in contemporary biophysics and structural biology is a quantitative understanding of the linkages among protein structure, dynamics, and function. These linkages are becoming increasingly explorable due to conceptual and methodological advances. In this Perspective article, we will point toward future directions of the field of protein dynamics with an emphasis on enzymes. Research questions in the field are becoming increasingly complex such as the mechanistic understanding of high-order interaction networks in allosteric signal propagation through a protein matrix, or the connection between local and collective motions. In analogy to the solution to the "protein folding problem," we argue that the way forward to understanding these and other important questions lies in the successful integration of experiment and computation, while utilizing the present rapid expansion of sequence and structure space. Looking forward, the future is bright, and we are in a period where we are on the doorstep to, at least in part, comprehend the importance of dynamics for biological function.
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Affiliation(s)
- Kwangho Nam
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, Texas 76019, USA
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15
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van Wijk N, Zohar K, Linial M. Challenging Cellular Homeostasis: Spatial and Temporal Regulation of miRNAs. Int J Mol Sci 2022; 23:16152. [PMID: 36555797 PMCID: PMC9787707 DOI: 10.3390/ijms232416152] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 12/11/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022] Open
Abstract
Mature microRNAs (miRNAs) are single-stranded non-coding RNA (ncRNA) molecules that act in post-transcriptional regulation in animals and plants. A mature miRNA is the end product of consecutive, highly regulated processing steps of the primary miRNA transcript. Following base-paring of the mature miRNA with its mRNA target, translation is inhibited, and the targeted mRNA is degraded. There are hundreds of miRNAs in each cell that work together to regulate cellular key processes, including development, differentiation, cell cycle, apoptosis, inflammation, viral infection, and more. In this review, we present an overlooked layer of cellular regulation that addresses cell dynamics affecting miRNA accessibility. We discuss the regulation of miRNA local storage and translocation among cell compartments. The local amounts of the miRNAs and their targets dictate their actual availability, which determines the ability to fine-tune cell responses to abrupt or chronic changes. We emphasize that changes in miRNA storage and compactization occur under induced stress and changing conditions. Furthermore, we demonstrate shared principles on cell physiology, governed by miRNA under oxidative stress, tumorigenesis, viral infection, or synaptic plasticity. The evidence presented in this review article highlights the importance of spatial and temporal miRNA regulation for cell physiology. We argue that limiting the research to mature miRNAs within the cytosol undermines our understanding of the efficacy of miRNAs to regulate cell fate under stress conditions.
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Affiliation(s)
| | | | - Michal Linial
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Faculty of Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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Liu Y, Li B, Liu B, Zhang K. Single-Particle Optical Imaging for Ultrasensitive Bioanalysis. BIOSENSORS 2022; 12:1105. [PMID: 36551072 PMCID: PMC9775667 DOI: 10.3390/bios12121105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 11/23/2022] [Accepted: 11/28/2022] [Indexed: 06/17/2023]
Abstract
The quantitative detection of critical biomolecules and in particular low-abundance biomarkers in biofluids is crucial for early-stage diagnosis and management but remains a challenge largely owing to the insufficient sensitivity of existing ensemble-sensing methods. The single-particle imaging technique has emerged as an important tool to analyze ultralow-abundance biomolecules by engineering and exploiting the distinct physical and chemical property of individual luminescent particles. In this review, we focus and survey the latest advances in single-particle optical imaging (OSPI) for ultrasensitive bioanalysis pertaining to basic biological studies and clinical applications. We first introduce state-of-the-art OSPI techniques, including fluorescence, surface-enhanced Raman scattering, electrochemiluminescence, and dark-field scattering, with emphasis on the contributions of various metal and nonmetal nano-labels to the improvement of the signal-to-noise ratio. During the discussion of individual techniques, we also highlight their applications in spatial-temporal measurement of key biomarkers such as proteins, nucleic acids and extracellular vesicles with single-entity sensitivity. To that end, we discuss the current challenges and prospective trends of single-particle optical-imaging-based bioanalysis.
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Affiliation(s)
- Yujie Liu
- Shanghai Institute of Pediatric Research, Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Xin Hua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - Binxiao Li
- Department of Chemistry, Shanghai Stomatological Hospital, State Key Lab of Molecular Engineering of Polymers, Institutes of Biomedical Sciences, Fudan University, Shanghai 200438, China
| | - Baohong Liu
- Department of Chemistry, Shanghai Stomatological Hospital, State Key Lab of Molecular Engineering of Polymers, Institutes of Biomedical Sciences, Fudan University, Shanghai 200438, China
| | - Kun Zhang
- Shanghai Institute of Pediatric Research, Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Xin Hua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
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Koopal B, Mutte SK, Swarts DC. A long look at short prokaryotic Argonautes. Trends Cell Biol 2022:S0962-8924(22)00239-2. [DOI: 10.1016/j.tcb.2022.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 10/23/2022] [Accepted: 10/31/2022] [Indexed: 11/23/2022]
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