1
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Qiu C, Zhang Z, Wine RN, Campbell ZT, Zhang J, Hall TMT. Intra- and inter-molecular regulation by intrinsically-disordered regions governs PUF protein RNA binding. Nat Commun 2023; 14:7323. [PMID: 37953271 PMCID: PMC10641069 DOI: 10.1038/s41467-023-43098-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 10/30/2023] [Indexed: 11/14/2023] Open
Abstract
PUF proteins are characterized by globular RNA-binding domains. They also interact with partner proteins that modulate their RNA-binding activities. Caenorhabditis elegans PUF protein fem-3 binding factor-2 (FBF-2) partners with intrinsically disordered Lateral Signaling Target-1 (LST-1) to regulate target mRNAs in germline stem cells. Here, we report that an intrinsically disordered region (IDR) at the C-terminus of FBF-2 autoinhibits its RNA-binding affinity by increasing the off rate for RNA binding. Moreover, the FBF-2 C-terminal region interacts with its globular RNA-binding domain at the same site where LST-1 binds. This intramolecular interaction restrains an electronegative cluster of amino acid residues near the 5' end of the bound RNA to inhibit RNA binding. LST-1 binding in place of the FBF-2 C-terminus therefore releases autoinhibition and increases RNA-binding affinity. This regulatory mechanism, driven by IDRs, provides a biochemical and biophysical explanation for the interdependence of FBF-2 and LST-1 in germline stem cell self-renewal.
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Affiliation(s)
- Chen Qiu
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA
| | - Zihan Zhang
- Department of Chemistry, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Robert N Wine
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA
| | - Zachary T Campbell
- Department of Anesthesiology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Jun Zhang
- Department of Chemistry, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Traci M Tanaka Hall
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA.
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2
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Webster AK, Willis JH, Johnson E, Sarkies P, Phillips PC. Epigenetic context predicts gene expression variation and reproductive traits across genetically identical individuals. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.13.562270. [PMID: 37873136 PMCID: PMC10592811 DOI: 10.1101/2023.10.13.562270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
In recent decades, genome-wide association studies (GWAS) have been the major approach to understand the biological basis of individual differences in traits and diseases. However, GWAS approaches have proven to have limited predictive power to explain individual differences, particularly for complex traits and diseases in which environmental factors play a substantial role in their etiology. Indeed, individual differences persist even in genetically identical individuals, although fully separating genetic and environmental causation is difficult or impossible in most organisms. To understand the basis of individual differences in the absence of genetic differences, we measured two quantitative reproductive traits in 180 genetically identical young adult Caenorhabditis elegans roundworms in a shared environment and performed single-individual transcriptomics on each worm. We identified hundreds of genes for which expression variation was strongly associated with reproductive traits, some of which depended on prior environmental experience and some of which was random. Multiple small sets of genes together were highly predictive of reproductive traits across individuals, explaining on average over half and over a quarter of variation in the two traits. We manipulated mRNA levels of predictive genes using RNA interference to identify a set of causal genes, demonstrating the utility of this approach for both prediction and understanding underlying biology. Finally, we found that the chromatin environment of predictive genes was enriched for H3K27 trimethylation, suggesting that individual gene expression differences underlying critical traits may be driven in part by chromatin structure. Together, this work shows that individual differences in gene expression that arise independently of underlying genetic differences are both predictive and causal in shaping reproductive traits at levels that equal or exceed genetic variation.
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3
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Cardona AH, Ecsedi S, Khier M, Yi Z, Bahri A, Ouertani A, Valero F, Labrosse M, Rouquet S, Robert S, Loubat A, Adekunle D, Hubstenberger A. Self-demixing of mRNA copies buffers mRNA:mRNA and mRNA:regulator stoichiometries. Cell 2023; 186:4310-4324.e23. [PMID: 37703874 DOI: 10.1016/j.cell.2023.08.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 06/08/2023] [Accepted: 08/16/2023] [Indexed: 09/15/2023]
Abstract
Cellular homeostasis requires the robust control of biomolecule concentrations, but how do millions of mRNAs coordinate their stoichiometries in the face of dynamic translational changes? Here, we identified a two-tiered mechanism controlling mRNA:mRNA and mRNA:protein stoichiometries where mRNAs super-assemble into condensates with buffering capacity and sorting selectivity through phase-transition mechanisms. Using C. elegans oogenesis arrest as a model, we investigated the transcriptome cytosolic reorganization through the sequencing of RNA super-assemblies coupled with single mRNA imaging. Tightly repressed mRNAs self-assembled into same-sequence nanoclusters that further co-assembled into multiphase condensates. mRNA self-sorting was concentration dependent, providing a self-buffering mechanism that is selective to sequence identity and controls mRNA:mRNA stoichiometries. The cooperative sharing of limiting translation repressors between clustered mRNAs prevented the disruption of mRNA:repressor stoichiometries in the cytosol. Robust control of mRNA:mRNA and mRNA:protein stoichiometries emerges from mRNA self-demixing and cooperative super-assembly into multiphase multiscale condensates with dynamic storage capacity.
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Affiliation(s)
| | - Szilvia Ecsedi
- Université Côte D'Azur, CNRS, Inserm, iBV, 06108 Nice, France
| | - Mokrane Khier
- Université Côte D'Azur, CNRS, Inserm, iBV, 06108 Nice, France
| | - Zhou Yi
- Université Côte D'Azur, CNRS, Inserm, iBV, 06108 Nice, France
| | - Alia Bahri
- Université Côte D'Azur, CNRS, Inserm, iBV, 06108 Nice, France
| | - Amira Ouertani
- Université Côte D'Azur, CNRS, Inserm, iBV, 06108 Nice, France
| | - Florian Valero
- Université Côte D'Azur, CNRS, Inserm, iBV, 06108 Nice, France
| | | | - Sami Rouquet
- Université Côte D'Azur, CNRS, Inserm, iBV, 06108 Nice, France
| | - Stéphane Robert
- Université Aix Marseille, Inserm, INRAE, C2VN, 13005 Marseille, France
| | - Agnès Loubat
- Université Côte D'Azur, CNRS, Inserm, iBV, 06108 Nice, France
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4
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Albarqi MMY, Ryder SP. The role of RNA-binding proteins in orchestrating germline development in Caenorhabditis elegans. Front Cell Dev Biol 2023; 10:1094295. [PMID: 36684428 PMCID: PMC9846511 DOI: 10.3389/fcell.2022.1094295] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 12/19/2022] [Indexed: 01/06/2023] Open
Abstract
RNA passed from parents to progeny controls several aspects of early development. The germline of the free-living nematode Caenorhabditis elegans contains many families of evolutionarily conserved RNA-binding proteins (RBPs) that target the untranslated regions of mRNA transcripts to regulate their translation and stability. In this review, we summarize what is known about the binding specificity of C. elegans germline RNA-binding proteins and the mechanisms of mRNA regulation that contribute to their function. We examine the emerging role of miRNAs in translational regulation of germline and embryo development. We also provide an overview of current technology that can be used to address the gaps in our understanding of RBP regulation of mRNAs. Finally, we present a hypothetical model wherein multiple 3'UTR-mediated regulatory processes contribute to pattern formation in the germline to ensure the proper and timely localization of germline proteins and thus a functional reproductive system.
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5
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Vanden Broek K, Han X, Hansen D. Redundant mechanisms regulating the proliferation vs. differentiation balance in the C. elegans germline. Front Cell Dev Biol 2022; 10:960999. [PMID: 36120589 PMCID: PMC9479330 DOI: 10.3389/fcell.2022.960999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 08/15/2022] [Indexed: 11/21/2022] Open
Abstract
The proper production of gametes over an extended portion of the life of an organism is essential for a high level of fitness. The balance between germline stem cell (GSC) proliferation (self-renewal) and differentiation (production of gametes) must be tightly regulated to ensure proper gamete production and overall fitness. Therefore, organisms have evolved robust regulatory systems to control this balance. Here we discuss the redundancy in the regulatory system that controls the proliferation vs. differentiation balance in the C. elegans hermaphrodite germline, and how this redundancy may contribute to robustness. We focus on the various types of redundancy utilized to regulate this balance, as well as the approaches that have enabled these redundant mechanisms to be uncovered.
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6
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The Role of Pumilio RNA Binding Protein in Plants. Biomolecules 2021; 11:biom11121851. [PMID: 34944494 PMCID: PMC8699478 DOI: 10.3390/biom11121851] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Revised: 12/01/2021] [Accepted: 12/07/2021] [Indexed: 11/27/2022] Open
Abstract
Eukaryotic organisms have a posttranscriptional/translational regulation system for the control of translational efficiency. RNA binding proteins (RBPs) have been known to control target genes. One type of protein, Pumilio (Pum)/Puf family RNA binding proteins, show a specific binding of 3′ untranslational region (3′ UTR) of target mRNA and function as a post-transcriptional/translational regulator in eukaryotic cells. Plant Pum protein is involved in development and biotic/abiotic stresses. Interestingly, Arabidopsis Pum can control target genes in a sequence-specific manner and rRNA processing in a sequence-nonspecific manner. As shown in in silico Pum gene expression analysis, Arabidopsis and rice Pum genes are responsive to biotic/abiotic stresses. Plant Pum can commonly contribute to host gene regulation at the post-transcriptional/translational step, as can mammalian Pum. However, the function of plant Pum proteins is not yet fully known. In this review, we briefly summarize the function of plant Pum in defense, development, and environmental responses via recent research and bioinformatics data.
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7
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Wang X, Ellenbecker M, Hickey B, Day NJ, Osterli E, Terzo M, Voronina E. Antagonistic control of Caenorhabditis elegans germline stem cell proliferation and differentiation by PUF proteins FBF-1 and FBF-2. eLife 2020; 9:52788. [PMID: 32804074 PMCID: PMC7467723 DOI: 10.7554/elife.52788] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 08/14/2020] [Indexed: 02/07/2023] Open
Abstract
Stem cells support tissue maintenance, but the mechanisms that coordinate the rate of stem cell self-renewal with differentiation at a population level remain uncharacterized. We find that two PUF family RNA-binding proteins FBF-1 and FBF-2 have opposite effects on Caenorhabditis elegans germline stem cell dynamics: FBF-1 restricts the rate of meiotic entry, while FBF-2 promotes both cell division and meiotic entry rates. Antagonistic effects of FBFs are mediated by their distinct activities toward the shared set of target mRNAs, where FBF-1-mediated post-transcriptional control requires the activity of CCR4-NOT deadenylase, while FBF-2 is deadenylase-independent and might protect the targets from deadenylation. These regulatory differences depend on protein sequences outside of the conserved PUF family RNA-binding domain. We propose that the opposing FBF-1 and FBF-2 activities serve to modulate stem cell division rate simultaneously with the rate of meiotic entry.
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Affiliation(s)
- Xiaobo Wang
- Division of Biological Sciences, University of Montana, Missoula, United States
| | - Mary Ellenbecker
- Division of Biological Sciences, University of Montana, Missoula, United States
| | - Benjamin Hickey
- Division of Biological Sciences, University of Montana, Missoula, United States
| | - Nicholas J Day
- Division of Biological Sciences, University of Montana, Missoula, United States
| | - Emily Osterli
- Division of Biological Sciences, University of Montana, Missoula, United States
| | - Mikaya Terzo
- Division of Biological Sciences, University of Montana, Missoula, United States
| | - Ekaterina Voronina
- Division of Biological Sciences, University of Montana, Missoula, United States
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8
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Bhondeley M, Liu Z. Mitochondrial Biogenesis Is Positively Regulated by Casein Kinase I Hrr25 Through Phosphorylation of Puf3 in Saccharomyces cerevisiae. Genetics 2020; 215:463-482. [PMID: 32317286 PMCID: PMC7268985 DOI: 10.1534/genetics.120.303191] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 04/20/2020] [Indexed: 11/18/2022] Open
Abstract
Mitochondrial biogenesis requires coordinated expression of genes encoding mitochondrial proteins, which in Saccharomyces cerevisiae is achieved in part via post-transcriptional control by the Pumilio RNA-binding domain protein Puf3 Puf3 binds to the 3'-UTR of many messenger RNAs (mRNAs) that encode mitochondrial proteins, regulating their turnover, translation, and/or mitochondrial targeting. Puf3 hyperphosphorylation correlates with increased mitochondrial biogenesis; however, the kinase responsible for Puf3 phosphorylation is unclear. Here, we show that the casein kinase I protein Hrr25 negatively regulates Puf3 by mediating its phosphorylation. An hrr25 mutation results in reduced phosphorylation of Puf3 in vivo and a puf3 deletion mutation reverses growth defects of hrr25 mutant cells grown on medium with a nonfermentable carbon source. We show that Hrr25 directly phosphorylates Puf3, and that the interaction between Puf3 and Hrr25 is mediated through the N-terminal domain of Puf3 and the kinase domain of Hrr25 We further found that an hrr25 mutation reduces GFP expression from GFP reporter constructs carrying the 3'-UTR of Puf3 targets. Downregulation of GFP expression due to an hrr25 mutation can be reversed either by puf3Δ or by mutations to the Puf3-binding sites in the 3'-UTR of the GFP reporter constructs. Together, our data indicate that Hrr25 is a positive regulator of mitochondrial biogenesis by phosphorylating Puf3 and inhibiting its function in downregulating target mRNAs encoding mitochondrial proteins.
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Affiliation(s)
- Manika Bhondeley
- Department of Biological Sciences, University of New Orleans, Louisiana 70148
| | - Zhengchang Liu
- Department of Biological Sciences, University of New Orleans, Louisiana 70148
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9
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Wang X, Voronina E. Diverse Roles of PUF Proteins in Germline Stem and Progenitor Cell Development in C. elegans. Front Cell Dev Biol 2020; 8:29. [PMID: 32117964 PMCID: PMC7015873 DOI: 10.3389/fcell.2020.00029] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 01/14/2020] [Indexed: 01/05/2023] Open
Abstract
Stem cell development depends on post-transcriptional regulation mediated by RNA-binding proteins (RBPs) (Zhang et al., 1997; Forbes and Lehmann, 1998; Okano et al., 2005; Ratti et al., 2006; Kwon et al., 2013). Pumilio and FBF (PUF) family RBPs are highly conserved post-transcriptional regulators that are critical for stem cell maintenance (Wickens et al., 2002; Quenault et al., 2011). The RNA-binding domains of PUF proteins recognize a family of related sequence motifs in the target mRNAs, yet individual PUF proteins have clearly distinct biological functions (Lu et al., 2009; Wang et al., 2018). The C. elegans germline is a simple and powerful model system for analyzing regulation of stem cell development. Studies in C. elegans uncovered specific physiological roles for PUFs expressed in the germline stem cells ranging from control of proliferation and differentiation to regulation of the sperm/oocyte decision. Importantly, recent studies started to illuminate the mechanisms behind PUF functional divergence. This review summarizes the many roles of PUF-8, FBF-1, and FBF-2 in germline stem and progenitor cells (SPCs) and discusses the factors accounting for their distinct biological functions. PUF proteins are conserved in evolution, and insights into PUF-mediated regulation provided by the C. elegans model system are likely relevant for other organisms.
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Affiliation(s)
- Xiaobo Wang
- Division of Biological Sciences, University of Montana, Missoula, MT, United States
| | - Ekaterina Voronina
- Division of Biological Sciences, University of Montana, Missoula, MT, United States
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10
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Bhat VD, McCann KL, Wang Y, Fonseca DR, Shukla T, Alexander JC, Qiu C, Wickens M, Lo TW, Tanaka Hall TM, Campbell ZT. Engineering a conserved RNA regulatory protein repurposes its biological function in vivo. eLife 2019; 8:43788. [PMID: 30652968 PMCID: PMC6351103 DOI: 10.7554/elife.43788] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 01/15/2019] [Indexed: 12/18/2022] Open
Abstract
PUF (PUmilio/FBF) RNA-binding proteins recognize distinct elements. In C. elegans, PUF-8 binds to an 8-nt motif and restricts proliferation in the germline. Conversely, FBF-2 recognizes a 9-nt element and promotes mitosis. To understand how motif divergence relates to biological function, we first determined a crystal structure of PUF-8. Comparison of this structure to that of FBF-2 revealed a major difference in a central repeat. We devised a modified yeast 3-hybrid screen to identify mutations that confer recognition of an 8-nt element to FBF-2. We identified several such mutants and validated structurally and biochemically their binding to 8-nt RNA elements. Using genome engineering, we generated a mutant animal with a substitution in FBF-2 that confers preferential binding to the PUF-8 element. The mutant largely rescued overproliferation in animals that spontaneously generate tumors in the absence of puf-8. This work highlights the critical role of motif length in the specification of biological function.
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Affiliation(s)
- Vandita D Bhat
- Department of Biological Sciences, University of Texas Dallas, Richardson, United States
| | - Kathleen L McCann
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, United States
| | - Yeming Wang
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, United States
| | | | - Tarjani Shukla
- Department of Biological Sciences, University of Texas Dallas, Richardson, United States
| | | | - Chen Qiu
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, United States
| | - Marv Wickens
- Department of Biochemistry, University of Wisconsin-Madison, Madison, United States
| | - Te-Wen Lo
- Department of Biology, Ithaca College, Ithaca, United States
| | - Traci M Tanaka Hall
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, United States
| | - Zachary T Campbell
- Department of Biological Sciences, University of Texas Dallas, Richardson, United States
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11
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Wang M, Ogé L, Perez-Garcia MD, Hamama L, Sakr S. The PUF Protein Family: Overview on PUF RNA Targets, Biological Functions, and Post Transcriptional Regulation. Int J Mol Sci 2018; 19:ijms19020410. [PMID: 29385744 PMCID: PMC5855632 DOI: 10.3390/ijms19020410] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2018] [Revised: 01/23/2018] [Accepted: 01/25/2018] [Indexed: 12/13/2022] Open
Abstract
Post-transcriptional regulation of gene expression plays a crucial role in many processes. In cells, it is mediated by diverse RNA-binding proteins. These proteins can influence mRNA stability, translation, and localization. The PUF protein family (Pumilio and FBF) is composed of RNA-binding proteins highly conserved among most eukaryotic organisms. Previous investigations indicated that they could be involved in many processes by binding corresponding motifs in the 3′UTR or by interacting with other proteins. To date, most of the investigations on PUF proteins have been focused on Caenorhabditis elegans, Drosophila melanogaster, and Saccharomyces cerevisiae, while only a few have been conducted on Arabidopsis thaliana. The present article provides an overview of the PUF protein family. It addresses their RNA-binding motifs, biological functions, and post-transcriptional control mechanisms in Caenorhabditis elegans, Drosophila melanogaster, Saccharomyces cerevisiae, and Arabidopsis thaliana. These items of knowledge open onto new investigations into the relevance of PUF proteins in specific plant developmental processes.
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Affiliation(s)
- Ming Wang
- IRHS, Agrocampus-Ouest, INRA, Université d'Angers, SFR 4207 QUASAV, F-49045 Angers, France.
| | - Laurent Ogé
- IRHS, Agrocampus-Ouest, INRA, Université d'Angers, SFR 4207 QUASAV, F-49045 Angers, France.
| | | | - Latifa Hamama
- IRHS, Agrocampus-Ouest, INRA, Université d'Angers, SFR 4207 QUASAV, F-49045 Angers, France.
| | - Soulaiman Sakr
- IRHS, Agrocampus-Ouest, INRA, Université d'Angers, SFR 4207 QUASAV, F-49045 Angers, France.
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12
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Tamburino AM, Kaymak E, Shrestha S, Holdorf AD, Ryder SP, Walhout AJM. PRIMA: a gene-centered, RNA-to-protein method for mapping RNA-protein interactions. ACTA ACUST UNITED AC 2017; 5:e1295130. [PMID: 28702278 DOI: 10.1080/21690731.2017.1295130] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 01/23/2017] [Accepted: 02/09/2017] [Indexed: 12/20/2022]
Abstract
Interactions between RNA binding proteins (RBPs) and mRNAs are critical to post-transcriptional gene regulation. Eukaryotic genomes encode thousands of mRNAs and hundreds of RBPs. However, in contrast to interactions between transcription factors (TFs) and DNA, the interactome between RBPs and RNA has been explored for only a small number of proteins and RNAs. This is largely because the focus has been on using 'protein-centered' (RBP-to-RNA) interaction mapping methods that identify the RNAs with which an individual RBP interacts. While powerful, these methods cannot as of yet be applied to the entire RBPome. Moreover, it may be desirable for a researcher to identify the repertoire of RBPs that can interact with an mRNA of interest-in a 'gene-centered' manner-yet few such techniques are available. Here, we present Protein-RNA Interaction Mapping Assay (PRIMA) with which an RNA 'bait' can be tested versus multiple RBP 'preys' in a single experiment. PRIMA is a translation-based assay that examines interactions in the yeast cytoplasm, the cellular location of mRNA translation. We show that PRIMA can be used with small RNA elements, as well as with full-length Caenorhabditis elegans 3' UTRs. PRIMA faithfully recapitulated numerous well-characterized RNA-RBP interactions and also identified novel interactions, some of which were confirmed in vivo. We envision that PRIMA will provide a complementary tool to expand the depth and scale with which the RNA-RBP interactome can be explored.
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Affiliation(s)
- Alex M Tamburino
- Program in Systems Biology and Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | - Ebru Kaymak
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Shaleen Shrestha
- Program in Systems Biology and Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | - Amy D Holdorf
- Program in Systems Biology and Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | - Sean P Ryder
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Albertha J M Walhout
- Program in Systems Biology and Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, USA
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13
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Hogan GJ, Brown PO, Herschlag D. Evolutionary Conservation and Diversification of Puf RNA Binding Proteins and Their mRNA Targets. PLoS Biol 2015; 13:e1002307. [PMID: 26587879 PMCID: PMC4654594 DOI: 10.1371/journal.pbio.1002307] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 10/23/2015] [Indexed: 12/31/2022] Open
Abstract
Reprogramming of a gene’s expression pattern by acquisition and loss of sequences recognized by specific regulatory RNA binding proteins may be a major mechanism in the evolution of biological regulatory programs. We identified that RNA targets of Puf3 orthologs have been conserved over 100–500 million years of evolution in five eukaryotic lineages. Focusing on Puf proteins and their targets across 80 fungi, we constructed a parsimonious model for their evolutionary history. This model entails extensive and coordinated changes in the Puf targets as well as changes in the number of Puf genes and alterations of RNA binding specificity including that: 1) Binding of Puf3 to more than 200 RNAs whose protein products are predominantly involved in the production and organization of mitochondrial complexes predates the origin of budding yeasts and filamentous fungi and was maintained for 500 million years, throughout the evolution of budding yeast. 2) In filamentous fungi, remarkably, more than 150 of the ancestral Puf3 targets were gained by Puf4, with one lineage maintaining both Puf3 and Puf4 as regulators and a sister lineage losing Puf3 as a regulator of these RNAs. The decrease in gene expression of these mRNAs upon deletion of Puf4 in filamentous fungi (N. crassa) in contrast to the increase upon Puf3 deletion in budding yeast (S. cerevisiae) suggests that the output of the RNA regulatory network is different with Puf4 in filamentous fungi than with Puf3 in budding yeast. 3) The coregulated Puf4 target set in filamentous fungi expanded to include mitochondrial genes involved in the tricarboxylic acid (TCA) cycle and other nuclear-encoded RNAs with mitochondrial function not bound by Puf3 in budding yeast, observations that provide additional evidence for substantial rewiring of post-transcriptional regulation. 4) Puf3 also expanded and diversified its targets in filamentous fungi, gaining interactions with the mRNAs encoding the mitochondrial electron transport chain (ETC) complex I as well as hundreds of other mRNAs with nonmitochondrial functions. The many concerted and conserved changes in the RNA targets of Puf proteins strongly support an extensive role of RNA binding proteins in coordinating gene expression, as originally proposed by Keene. Rewiring of Puf-coordinated mRNA targets and transcriptional control of the same genes occurred at different points in evolution, suggesting that there have been distinct adaptations via RNA binding proteins and transcription factors. The changes in Puf targets and in the Puf proteins indicate an integral involvement of RNA binding proteins and their RNA targets in the adaptation, reprogramming, and function of gene expression. A map of the evolutionary history of Puf proteins and their RNA targets shows that reprogramming of global gene expression programs via adaptive mutations that affect protein-RNA interactions is an important source of biological diversity. We set out to trace the evolutionary history of an RNA binding protein and how its interactions with targets change over evolution. Identifying this natural history is a step toward understanding the critical differences between organisms and how gene expression programs are rewired during evolution. Using bioinformatics and experimental approaches, we broadly surveyed the evolution of binding targets of a particular family of RNA binding proteins—the Puf proteins, whose protein sequences and target RNA sequences are relatively well-characterized—across 99 eukaryotic species. We found five groups of species in which targets have been conserved for at least 100 million years and then took advantage of genome sequences from a large number of fungal species to deeply investigate the conservation and changes in Puf proteins and their RNA targets. Our analyses identified multiple and extensive reconfigurations during the natural history of fungi and suggest that RNA binding proteins and their RNA targets are profoundly involved in evolutionary reprogramming of gene expression and help define distinct programs unique to each organism. Continuing to uncover the natural history of RNA binding proteins and their interactions will provide a unique window into the gene expression programs of present day species and point to new ways to engineer gene expression programs.
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Affiliation(s)
- Gregory J. Hogan
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California, United States of America
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, California, United States of America
| | - Patrick O. Brown
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California, United States of America
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, California, United States of America
- * E-mail: (POB); (DH)
| | - Daniel Herschlag
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California, United States of America
- Department of Chemistry, Stanford University, Stanford, California, United States of America
- Department of Chemical Engineering, Stanford University, Stanford, California, United States of America
- ChEM-H Institute, Stanford University, Stanford, California, United States of America
- * E-mail: (POB); (DH)
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14
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Hubstenberger A, Cameron C, Noble SL, Keenan S, Evans TC. Modifiers of solid RNP granules control normal RNP dynamics and mRNA activity in early development. J Cell Biol 2015; 211:703-16. [PMID: 26527741 PMCID: PMC4639854 DOI: 10.1083/jcb.201504044] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 09/25/2015] [Indexed: 12/13/2022] Open
Abstract
Modifiers of aberrant solid RNP granules suggest new insights into pathways that control dynamics of large-scale RNP bodies and mRNAs during C. elegans oogenesis. Ribonucleoproteins (RNPs) often coassemble into supramolecular bodies with regulated dynamics. The factors controlling RNP bodies and connections to RNA regulation are unclear. During Caenorhabditis elegans oogenesis, cytoplasmic RNPs can transition among diffuse, liquid, and solid states linked to mRNA regulation. Loss of CGH-1/Ddx6 RNA helicase generates solid granules that are sensitive to mRNA regulators. Here, we identified 66 modifiers of RNP solids induced by cgh-1 mutation. A majority of genes promote or suppress normal RNP body assembly, dynamics, or metabolism. Surprisingly, polyadenylation factors promote RNP coassembly in vivo, suggesting new functions of poly(A) tail regulation in RNP dynamics. Many genes carry polyglutatmine (polyQ) motifs or modulate polyQ aggregation, indicating possible connections with neurodegenerative disorders induced by CAG/polyQ expansion. Several RNP body regulators repress translation of mRNA subsets, suggesting that mRNAs are repressed by multiple mechanisms. Collectively, these findings suggest new pathways of RNP modification that control large-scale coassembly and mRNA activity during development.
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Affiliation(s)
- Arnaud Hubstenberger
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045 Pierre-and-Marie-Curie University, University Paris 06, 75005 Paris, France
| | - Cristiana Cameron
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Scott L Noble
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045 Graduate Program in Molecular Biology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Sean Keenan
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Thomas C Evans
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
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15
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Clayton CE. Networks of gene expression regulation in Trypanosoma brucei. Mol Biochem Parasitol 2014; 195:96-106. [PMID: 24995711 DOI: 10.1016/j.molbiopara.2014.06.005] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 06/19/2014] [Accepted: 06/23/2014] [Indexed: 10/25/2022]
Abstract
Regulation of gene expression in Kinetoplastids relies mainly on post-transcriptional mechanisms. Recent high-throughput analyses, combined with mathematical modelling, have demonstrated possibilities for transcript-specific regulation at every stage: trans splicing, polyadenylation, translation, and degradation of both the precursor and the mature mRNA. Different mRNA degradation pathways result in different types of degradation kinetics. The original idea that the fate of an mRNA - or even just its degradation kinetics - can be defined by a single "regulatory element" is an over-simplification. It is now clear that every mRNA can bind many different proteins, some of which may compete with each other. Superimposed upon this complexity are the interactions of those proteins with effectors of gene expression. The amount of protein that is made from a gene is therefore determined by a complex network of interactions.
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Affiliation(s)
- C E Clayton
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany.
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16
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Campbell ZT, Valley CT, Wickens M. A protein-RNA specificity code enables targeted activation of an endogenous human transcript. Nat Struct Mol Biol 2014; 21:732-8. [PMID: 24997599 PMCID: PMC4125476 DOI: 10.1038/nsmb.2847] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 05/30/2014] [Indexed: 12/27/2022]
Abstract
Programmable protein scaffolds that target DNA are invaluable tools for genome engineering and designer control of transcription. RNA manipulation provides broad new opportunities for control, including changes in translation. PUF proteins are an attractive platform for that purpose because they bind specific single-stranded RNA sequences by using short repeated modules, each contributing three amino acids that contact an RNA base. Here, we identified the specificities of natural and designed combinations of those three amino acids, using a large randomized RNA library. The resulting specificity code reveals the RNA binding preferences of natural proteins and enables the design of new specificities. Using the code and a translational activation domain, we designed a protein that targets endogenous cyclin B1 mRNA in human cells, increasing sensitivity to chemotherapeutic drugs. Our study provides a guide for rational design of engineered mRNA control, including translational stimulation.
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Affiliation(s)
- Zachary T Campbell
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Cary T Valley
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Marvin Wickens
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
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17
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Hubstenberger A, Noble SL, Cameron C, Evans TC. Translation repressors, an RNA helicase, and developmental cues control RNP phase transitions during early development. Dev Cell 2014; 27:161-173. [PMID: 24176641 DOI: 10.1016/j.devcel.2013.09.024] [Citation(s) in RCA: 124] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 08/27/2013] [Accepted: 09/26/2013] [Indexed: 12/27/2022]
Abstract
Like membranous organelles, large-scale coassembly of macromolecules can organize functions in cells. Ribonucleoproteins (RNPs) can form liquid or solid aggregates, but control and consequences of these RNP states in living, developing tissue are poorly understood. Here, we show that regulated RNP factor interactions drive transitions among diffuse, semiliquid, or solid states to modulate RNP sorting and exchange in the Caenorhabditis elegans oocyte cytoplasm. Translation repressors induce an intrinsic capacity of RNP components to coassemble into either large semiliquids or solid lattices, whereas a conserved RNA helicase prevents polymerization into nondynamic solids. Developmental cues dramatically alter both fluidity and sorting within large RNP assemblies, inducing a transition from RNP segregation in quiescent oocytes to dynamic exchange in the early embryo. Therefore, large-scale organization of gene expression extends to the cytoplasm, where regulation of supramolecular states imparts specific patterns of RNP dynamics.
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Affiliation(s)
- Arnaud Hubstenberger
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Scott L Noble
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Graduate Program in Molecular Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Cristiana Cameron
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Thomas C Evans
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA.
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18
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Abstract
The three-hybrid system can be used to identify RNA sequences that bind a specific protein by screening a hybrid RNA library with a protein-activation domain fusion as 'bait.' These screens complement biochemical techniques, for example, SELEX, co-immunoprecipitation, and cross-linking experiments (see UV crosslinking of interacting RNA and protein in cultured cells and PAR-CLIP (Photoactivatable Ribonucleoside-Enhanced Crosslinking and Immunoprecipitation): a step-by-step protocol to the transcriptome-wide identification of binding sites of RNA-binding proteins).
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19
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Miller MA, Russo J, Fischer AD, Lopez Leban FA, Olivas WM. Carbon source-dependent alteration of Puf3p activity mediates rapid changes in the stabilities of mRNAs involved in mitochondrial function. Nucleic Acids Res 2013; 42:3954-70. [PMID: 24371272 PMCID: PMC3973295 DOI: 10.1093/nar/gkt1346] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The Puf family of RNA-binding proteins regulates gene expression primarily by interacting with the 3′ untranslated region (3′ UTR) of targeted mRNAs and inhibiting translation and/or stimulating decay. Physical association and computational analyses of yeast Puf3p identified >150 potential mRNA targets involved in mitochondrial function. However, only COX17 has been established as a target of Puf3p-mediated deadenylation and decapping. We have identified 10 new targets that are rapidly degraded in a Puf3p-dependent manner. We also observed changes in Puf3p activity in response to environmental conditions. Puf3p promotes rapid degradation of mRNA targets in the fermentable carbon source dextrose. However, Puf3p-mediated decay activity is inhibited in carbon sources that require mitochondrial function for efficient cell growth. In addition, the activity of Puf3p is rapidly altered by changing the carbon source. PUF3 expression is not decreased at the RNA or protein level by different carbon sources and localization is not significantly altered, suggesting that Puf3p activity is regulated posttranslationally. Finally, under conditions when Puf3p is unable to stimulate decay, Puf3p can still bind its target mRNAs. Together, these experiments provide insight into the carbon source-specific control of Puf3p activity and how such alterations allow Puf3p to dynamically regulate mitochondrial function.
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Affiliation(s)
- Melanie A Miller
- Department of Biology, University of Missouri-St. Louis, St. Louis, MO 63121-4499, USA
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20
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Wang Y, Wang Z, Tanaka Hall TM. Engineered proteins with Pumilio/fem-3 mRNA binding factor scaffold to manipulate RNA metabolism. FEBS J 2013; 280:3755-67. [PMID: 23731364 DOI: 10.1111/febs.12367] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 05/29/2013] [Accepted: 05/30/2013] [Indexed: 01/13/2023]
Abstract
Pumilio/fem-3 mRNA binding factor proteins are characterized by a sequence-specific RNA-binding domain. This unique single-stranded RNA recognition module, whose sequence specificity can be reprogrammed, has been fused with functional modules to engineer protein factors with various functions. We summarize the advances made with respect to developing RNA regulatory tools, as well as opportunities for the future.
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Affiliation(s)
- Yang Wang
- Department of Pharmacology, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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21
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Translational control in the Caenorhabditis elegans germ line. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 757:205-47. [PMID: 22872479 DOI: 10.1007/978-1-4614-4015-4_8] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Translational control is a prevalent form of gene expression regulation in the Caenorhabditis elegans germ line. Linking the amount of protein synthesis to mRNA quantity and translational accessibility in the cell cytoplasm provides unique advantages over DNA-based controls for developing germ cells. This mode of gene expression is especially exploited in germ cell fate decisions and during oogenesis, when the developing oocytes stockpile hundreds of different mRNAs required for early embryogenesis. Consequently, a dense web of RNA regulators, consisting of diverse RNA-binding proteins and RNA-modifying enzymes, control the translatability of entire mRNA expression programs. These RNA regulatory networks are tightly coupled to germ cell developmental progression and are themselves under translational control. The underlying molecular mechanisms and RNA codes embedded in the mRNA molecules are beginning to be understood. Hence, the C. elegans germ line offers fertile grounds for discovering post-transcriptional mRNA regulatory mechanisms and emerges as great model for a systems level understanding of translational control during development.
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22
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PUF-8, a Pumilio homolog, inhibits the proliferative fate in the Caenorhabditis elegans germline. G3-GENES GENOMES GENETICS 2012; 2:1197-205. [PMID: 23050230 PMCID: PMC3464112 DOI: 10.1534/g3.112.003350] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Accepted: 08/06/2012] [Indexed: 01/10/2023]
Abstract
Stem cell populations are maintained by keeping a balance between self-renewal (proliferation) and differentiation of dividing stem cells. Within the Caenorhabditis elegans germline, the key regulator maintaining this balance is the canonical Notch signaling pathway, with GLP-1/Notch activity promoting the proliferative fate. We identified the Pumilio homolog, PUF-8, as an inhibitor of the proliferative fate of stem cells in the C. elegans germline. puf-8(0) strongly enhances overproliferation of glp-1(gf) mutants and partially suppresses underproliferation of a weak glp-1(lf) mutant. The germline tumor that is formed in a puf-8(0); glp-1(gf) double mutant is due to a failure of germ cells to enter meiotic prophase. puf-8 likely inhibits the proliferative fate through negatively regulating GLP-1/Notch signaling or by functioning parallel to it.
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23
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Martin F. Fifteen years of the yeast three-hybrid system: RNA-protein interactions under investigation. Methods 2012; 58:367-75. [PMID: 22841566 DOI: 10.1016/j.ymeth.2012.07.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Revised: 05/04/2012] [Accepted: 07/13/2012] [Indexed: 01/14/2023] Open
Abstract
In 1996, the Wickens and the Kuhl labs developed the yeast three-hybrid system independently. By expressing two chimeric proteins and one chimeric RNA molecule in Saccharomyces cerevisiae, this method allows in vivo monitoring of RNA-protein interactions by measuring the expression levels of HIS3 and LacZ reporter genes. Specific RNA targets have been used to characterize unknown RNA binding proteins. Previously described RNA binding proteins have also been used as bait to select new RNA targets. Finally, this method has been widely used to investigate or confirm previously suspected RNA-protein interactions. However, this method falls short in some aspects, such as RNA display and selection of false positive molecules. This review will summarize the results obtained with this method from the past 15years, as well as on recent efforts to improve its specificity.
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Affiliation(s)
- Franck Martin
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, Institut de Biologie Moléculaire et Cellulaire, Strasbourg CEDEX, France.
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24
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Hubstenberger A, Cameron C, Shtofman R, Gutman S, Evans TC. A network of PUF proteins and Ras signaling promote mRNA repression and oogenesis in C. elegans. Dev Biol 2012; 366:218-31. [PMID: 22542599 PMCID: PMC3361503 DOI: 10.1016/j.ydbio.2012.03.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Revised: 02/21/2012] [Accepted: 03/19/2012] [Indexed: 11/16/2022]
Abstract
Cell differentiation requires integration of gene expression controls with dynamic changes in cell morphology, function, and control. Post-transcriptional mRNA regulation and signaling systems are important to this process but their mechanisms and connections are unclear. During C. elegans oogenesis, we find that two groups of PUF RNA binding proteins (RNABPs), PUF-3/11 and PUF-5/6/7, control different specific aspects of oocyte formation. PUF-3/11 limits oocyte growth, while PUF-5/6/7 promotes oocyte organization and formation. These two PUF groups repress mRNA translation through overlapping but distinct sets of 3' untranslated regions (3'UTRs). Several PUF-dependent mRNAs encode other mRNA regulators suggesting both PUF groups control developmental patterning of mRNA regulation circuits. Furthermore, we find that the Ras-MapKinase/ERK pathway functions with PUF-5/6/7 to repress specific mRNAs and control oocyte organization and growth. These results suggest that diversification of PUF proteins and their integration with Ras-MAPK signaling modulates oocyte differentiation. Together with other studies, these findings suggest positive and negative interactions between the Ras-MAPK system and PUF RNA-binding proteins likely occur at multiple levels. Changes in these interactions over time can influence spatiotemporal patterning of tissue development.
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Affiliation(s)
- Arnaud Hubstenberger
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora CO 80045
| | - Cristiana Cameron
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora CO 80045
| | - Rebecca Shtofman
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora CO 80045
| | - Shiri Gutman
- Program in Cell biology, Stem Cells, and Development, University of Colorado Anschutz Medical Campus, Aurora CO 80045
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora CO 80045
| | - Thomas C. Evans
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora CO 80045
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25
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Patterns and plasticity in RNA-protein interactions enable recruitment of multiple proteins through a single site. Proc Natl Acad Sci U S A 2012; 109:6054-9. [PMID: 22467831 DOI: 10.1073/pnas.1200521109] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
mRNA control hinges on the specificity and affinity of proteins for their RNA binding sites. Regulatory proteins must bind their own sites and reject even closely related noncognate sites. In the PUF [Pumilio and fem-3 binding factor (FBF)] family of RNA binding proteins, individual proteins discriminate differences in the length and sequence of binding sites, allowing each PUF to bind a distinct battery of mRNAs. Here, we show that despite these differences, the pattern of RNA interactions is conserved among PUF proteins: the two ends of the PUF protein make critical contacts with the two ends of the RNA sites. Despite this conserved "two-handed" pattern of recognition, the RNA sequence is flexible. Among the binding sites of yeast Puf4p, RNA sequence dictates the pattern in which RNA bases are flipped away from the binding surface of the protein. Small differences in RNA sequence allow new modes of control, recruiting Puf5p in addition to Puf4p to a single site. This embedded information adds a new layer of biological meaning to the connections between RNA targets and PUF proteins.
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26
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Liu Q, Stumpf C, Thomas C, Wickens M, Haag ES. Context-dependent function of a conserved translational regulatory module. Development 2012; 139:1509-21. [PMID: 22399679 DOI: 10.1242/dev.070128] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The modification of transcriptional regulation is a well-documented evolutionary mechanism in both plants and animals, but post-transcriptional controls have received less attention. The derived hermaphrodite of C. elegans has regulated spermatogenesis in an otherwise female body. The PUF family RNA-binding proteins FBF-1 and FBF-2 limit XX spermatogenesis by repressing the male-promoting proteins FEM-3 and GLD-1. Here, we examine the function of PUF homologs from other Caenorhabditis species, with emphasis on C. briggsae, which evolved selfing convergently. C. briggsae lacks a bona fide fbf-1/2 ortholog, but two members of the related PUF-2 subfamily, Cbr-puf-2 and Cbr-puf-1.2, do have a redundant germline sex determination role. Surprisingly, this is to promote, rather than limit, hermaphrodite spermatogenesis. We provide genetic, molecular and biochemical evidence that Cbr-puf-2 and Cbr-puf-1.2 repress Cbr-gld-1 by a conserved mechanism. However, Cbr-gld-1 acts to limit, rather than promote, XX spermatogenesis. As with gld-1, no sex determination function for fbf or puf-2 orthologs is observed in gonochoristic Caenorhabditis. These results indicate that PUF family genes were co-opted for sex determination in each hermaphrodite via their long-standing association with gld-1, and that their precise sex-determining roles depend on the species-specific context in which they act. Finally, we document non-redundant roles for Cbr-puf-2 in embryonic and early larval development, the latter role being essential. Thus, recently duplicated PUF paralogs have already acquired distinct functions.
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Affiliation(s)
- Qinwen Liu
- Department of Biology, University of Maryland, College Park, MD 20742, USA
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27
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Cho SK, Kang IH, Carr T, Hannapel DJ. Using the Yeast Three-Hybrid System to Identify Proteins that Interact with a Phloem-Mobile mRNA. FRONTIERS IN PLANT SCIENCE 2012; 3:189. [PMID: 22969782 PMCID: PMC3427875 DOI: 10.3389/fpls.2012.00189] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Accepted: 08/02/2012] [Indexed: 05/02/2023]
Abstract
Heterografting and RNA transport experiments have demonstrated the long-distance mobility of StBEL5 RNA, its role in controlling tuber formation, and the function of the 503-nt 3' untranslated region (UTR) of the RNA in mediating transport. Because the 3' UTR of StBEL5 is a key element in regulating several aspects of RNA metabolism, a potato leaf cDNA library was screened using the 3' UTR of StBEL5 as bait in the yeast three-hybrid (Y3H) system to identify putative partner RNA-binding proteins (RBPs). From this screen, 116 positive cDNA clones were isolated based on nutrient selection, HIS3 activation, and lacZ induction and were sequenced and classified. Thirty-five proteins that were predicted to function in either RNA- or DNA-binding were selected from this pool. Seven were monitored for their expression profiles and further evaluated for their capacity to bind to the 3' UTR of StBEL5 using β-galactosidase assays in the Y3H system and RNA gel-shift assays. Among the final selections were two RBPs, a zinc finger protein, and one protein, StLSH10, from a family involved in light signaling. In this study, the Y3H system is presented as a valuable tool to screen and verify interactions between target RNAs and putative RBPs. These results can shed light on the dynamics and composition of plant RNA-protein complexes that function to regulate RNA metabolism.
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Affiliation(s)
- Sung Ki Cho
- Plant Biology Major, Iowa State University Ames, IA, USA
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28
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Qiu C, Kershner A, Wang Y, Holley CP, Wilinski D, Keles S, Kimble J, Wickens M, Hall TMT. Divergence of Pumilio/fem-3 mRNA binding factor (PUF) protein specificity through variations in an RNA-binding pocket. J Biol Chem 2011; 287:6949-57. [PMID: 22205700 DOI: 10.1074/jbc.m111.326264] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
mRNA control networks depend on recognition of specific RNA sequences. Pumilio-fem-3 mRNA binding factor (PUF) RNA-binding proteins achieve that specificity through variations on a conserved scaffold. Saccharomyces cerevisiae Puf3p achieves specificity through an additional binding pocket for a cytosine base upstream of the core RNA recognition site. Here we demonstrate that this chemically simple adaptation is prevalent and contributes to the diversity of RNA specificities among PUF proteins. Bioinformatics analysis shows that mRNAs associated with Caenorhabditis elegans fem-3 mRNA binding factor (FBF)-2 in vivo contain an upstream cytosine required for biological regulation. Crystal structures of FBF-2 and C. elegans PUF-6 reveal binding pockets structurally similar to that of Puf3p, whereas sequence alignments predict a pocket in PUF-11. For Puf3p, FBF-2, PUF-6, and PUF-11, the upstream pockets and a cytosine are required for maximal binding to RNA, but the quantitative impact on binding affinity varies. Furthermore, the position of the upstream cytosine relative to the core PUF recognition site can differ, which in the case of FBF-2 originally masked the identification of this consensus sequence feature. Importantly, other PUF proteins lack the pocket and so do not discriminate upstream bases. A structure-based alignment reveals that these proteins lack key residues that would contact the cytosine, and in some instances, they also present amino acid side chains that interfere with binding. Loss of the pocket requires only substitution of one serine, as appears to have occurred during the evolution of certain fungal species.
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Affiliation(s)
- Chen Qiu
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA
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29
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Yosefzon Y, Koh YY, Chritton JJ, Lande A, Leibovich L, Barziv L, Petzold C, Yakhini Z, Mandel-Gutfreund Y, Wickens M, Arava Y. Divergent RNA binding specificity of yeast Puf2p. RNA (NEW YORK, N.Y.) 2011; 17:1479-88. [PMID: 21685478 PMCID: PMC3153972 DOI: 10.1261/rna.2700311] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
PUF proteins bind mRNAs and regulate their translation, stability, and localization. Each PUF protein binds a selective group of mRNAs, enabling their coordinate control. We focus here on the specificity of Puf2p and Puf1p of Saccharomyces cerevisiae, which copurify with overlapping groups of mRNAs. We applied an RNA-adapted version of the DRIM algorithm to identify putative binding sequences for both proteins. We first identified a novel motif in the 3' UTRs of mRNAs previously shown to associate with Puf2p. This motif consisted of two UAAU tetranucleotides separated by a 3-nt linker sequence, which we refer to as the dual UAAU motif. The dual UAAU motif was necessary for binding to Puf2p, as judged by gel shift, yeast three-hybrid, and coimmunoprecipitation from yeast lysates. The UAAU tetranucleotides are required for optimal binding, while the identity and length of the linker sequences are less critical. Puf1p also binds the dual UAAU sequence, consistent with the prior observation that it associates with similar populations of mRNAs. In contrast, three other canonical yeast PUF proteins fail to bind the Puf2p recognition site. The dual UAAU motif is distinct from previously known PUF protein binding sites, which invariably possess a UGU trinucleotide. This study expands the repertoire of cis elements bound by PUF proteins and suggests new modes by which PUF proteins recognize their mRNA targets.
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Affiliation(s)
- Yahav Yosefzon
- Department of Biology, Technion–Israel Institute of Technology, Haifa 32000, Israel
| | - Yvonne Y. Koh
- Department of Biochemistry, University of Wisconsin–Madison, Madison, Wisconsin 53706, USA
| | - Jacqueline J. Chritton
- Department of Biochemistry, University of Wisconsin–Madison, Madison, Wisconsin 53706, USA
| | - Avigail Lande
- Department of Biology, Technion–Israel Institute of Technology, Haifa 32000, Israel
| | - Limor Leibovich
- Department of Computer Science, Technion–Israel Institute of Technology, Haifa 32000, Israel
| | - Lavi Barziv
- Department of Biology, Technion–Israel Institute of Technology, Haifa 32000, Israel
| | - Christine Petzold
- Department of Biochemistry, University of Wisconsin–Madison, Madison, Wisconsin 53706, USA
| | - Zohar Yakhini
- Department of Computer Science, Technion–Israel Institute of Technology, Haifa 32000, Israel
- Agilent Laboratories Israel, Petach-Tikva 49527, Israel
| | | | - Marvin Wickens
- Department of Biochemistry, University of Wisconsin–Madison, Madison, Wisconsin 53706, USA
- Corresponding authors.E-mail .E-mail .
| | - Yoav Arava
- Department of Biology, Technion–Israel Institute of Technology, Haifa 32000, Israel
- Corresponding authors.E-mail .E-mail .
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30
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Lu G, Hall TMT. Alternate modes of cognate RNA recognition by human PUMILIO proteins. Structure 2011; 19:361-7. [PMID: 21397187 DOI: 10.1016/j.str.2010.12.019] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Revised: 12/16/2010] [Accepted: 12/20/2010] [Indexed: 01/20/2023]
Abstract
Human PUMILIO1 (PUM1) and PUMILIO2 (PUM2) are members of the PUMILIO/FBF (PUF) family that regulate specific target mRNAs posttranscriptionally. Recent studies have identified mRNA targets associated with human PUM1 and PUM2. Here, we explore the structural basis of natural target RNA recognition by human PUF proteins through crystal structures of the RNA-binding domains of PUM1 and PUM2 in complex with four cognate RNA sequences, including sequences from p38α and erk2 MAP kinase mRNAs. We observe three distinct modes of RNA binding around the fifth RNA base, two of which are different from the prototypical 1 repeat:1 RNA base binding mode previously identified with model RNA sequences. RNA-binding affinities of PUM1 and PUM2 are not affected dramatically by the different binding modes in vitro. However, these modes of binding create structurally variable recognition surfaces that suggest a mechanism in vivo for recruitment of downstream effector proteins defined by the PUF:RNA complex.
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Affiliation(s)
- Gang Lu
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
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Zhang CD, Pan MH, Tan J, Li FF, Zhang J, Wang TT, Lu C. Characteristics and evolution of the PUF gene family in Bombyx mori and 27 other species. Mol Biol Rep 2011; 39:675-83. [PMID: 21598114 DOI: 10.1007/s11033-011-0785-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2011] [Accepted: 04/29/2011] [Indexed: 11/24/2022]
Abstract
The Pumilio protein is the founding member of the PUF family of RNA-binding proteins, which contains 8 repeat Puf domains and plays important roles during embryogenesis and post-embryogenesis by binding the Nanos response element (NRE) of specific target genes in eukaryotes. In addition, many other proteins containing the Puf domain were identified but with different functions from the Pumilio protein in various species. Taking advantage of the newly assembled genome sequences, in this study we performed a genome-wide analysis of PUF genes in silkworm and other 27 species. In the silkworm, three PUF genes were identified, named Bmpumilio, Bmpenguin and Bmnop by homology analysis. In fungi and animals, four evolutionarily conservational PUF gene families were identified, Group-A, -B, -C and -D. While Group-A, -C, and -D are present in all fungi and animals, Group-B was only identified in fungi. Interestingly, the number and features of the Puf domains are distinct in each group, suggesting different roles for these proteins in every group. The EST and microarray data showed that the mRNA of the three PUF genes can be widely detected in all tissues of the silkworm. Our results provide some new insights into the functions and evolutionary characteristics of PUF proteins.
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Affiliation(s)
- Chun-Dong Zhang
- The Key Sericultural Laboratory of Agricultural Ministry, Institute of Sericulture and Systems Biology, Southwest University, Chongqing, 400715, China
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Miller MA, Olivas WM. Roles of Puf proteins in mRNA degradation and translation. WILEY INTERDISCIPLINARY REVIEWS-RNA 2010; 2:471-92. [PMID: 21957038 DOI: 10.1002/wrna.69] [Citation(s) in RCA: 119] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Puf proteins are regulators of diverse eukaryotic processes including stem cell maintenance, organelle biogenesis, oogenesis, neuron function, and memory formation. At the molecular level, Puf proteins promote translational repression and/or degradation of target mRNAs by first interacting with conserved cis-elements in the 3' untranslated region (UTR). Once bound to an mRNA, Puf proteins elicit RNA repression by complex interactions with protein cofactors and regulatory machinery involved in translation and degradation. Recent work has dramatically increased our understanding of the targets of Puf protein regulation, as well as the mechanisms by which Puf proteins recognize and regulate those mRNA targets. Crystal structure analysis of several Puf-RNA complexes has demonstrated that while Puf proteins are extremely conserved in their RNA-binding domains, Pufs attain target specificity by utilizing different structural conformations to recognize 8-10 nt sequences. Puf proteins have also evolved modes of protein interactions that are organism and transcript-specific, yet two common mechanisms of repression have emerged: inhibition of cap-binding events to block translation initiation, and recruitment of the CCR4-POP2-NOT deadenylase complex for poly(A) tail removal. Finally, multiple schemes to regulate Puf protein activity have been identified, including post-translational mechanisms that allow rapid changes in the repression of mRNA targets.
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Affiliation(s)
- Melanie A Miller
- Department of Biology, University of Missouri-St. Louis, St. Louis, MO, USA
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Kaymak E, Wee LM, Ryder SP. Structure and function of nematode RNA-binding proteins. Curr Opin Struct Biol 2010; 20:305-12. [PMID: 20418095 DOI: 10.1016/j.sbi.2010.03.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2010] [Accepted: 03/29/2010] [Indexed: 01/27/2023]
Abstract
RNA-binding proteins are critical effectors of gene expression. They guide mRNA localization, translation, and stability, and potentially play a role in regulating mRNA synthesis. The structural basis for RNA recognition by RNA-binding proteins is the key to understand how they target specific transcripts for regulation. Compared to other metazoans, nematode genomes contain a significant expansion in several RNA-binding protein families, including Pumilio-FBF (PUF), TTP-like zinc finger (TZF), and Argonaute-like (AGO) proteins. Genetic data suggest that individual members of each family have distinct functions, presumably due to sequence variations that alter RNA-binding specificity or protein interaction partners. In this review, we highlight example structures and identify the variable regions that likely contribute to functional divergence in nematodes.
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Affiliation(s)
- Ebru Kaymak
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
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Tam PPC, Barrette-Ng IH, Simon DM, Tam MWC, Ang AL, Muench DG. The Puf family of RNA-binding proteins in plants: phylogeny, structural modeling, activity and subcellular localization. BMC PLANT BIOLOGY 2010; 10:44. [PMID: 20214804 PMCID: PMC2848763 DOI: 10.1186/1471-2229-10-44] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Accepted: 03/09/2010] [Indexed: 05/18/2023]
Abstract
BACKGROUND Puf proteins have important roles in controlling gene expression at the post-transcriptional level by promoting RNA decay and repressing translation. The Pumilio homology domain (PUM-HD) is a conserved region within Puf proteins that binds to RNA with sequence specificity. Although Puf proteins have been well characterized in animal and fungal systems, little is known about the structural and functional characteristics of Puf-like proteins in plants. RESULTS The Arabidopsis and rice genomes code for 26 and 19 Puf-like proteins, respectively, each possessing eight or fewer Puf repeats in their PUM-HD. Key amino acids in the PUM-HD of several of these proteins are conserved with those of animal and fungal homologs, whereas other plant Puf proteins demonstrate extensive variability in these amino acids. Three-dimensional modeling revealed that the predicted structure of this domain in plant Puf proteins provides a suitable surface for binding RNA. Electrophoretic gel mobility shift experiments showed that the Arabidopsis AtPum2 PUM-HD binds with high affinity to BoxB of the Drosophila Nanos Response Element I (NRE1) RNA, whereas a point mutation in the core of the NRE1 resulted in a significant reduction in binding affinity. Transient expression of several of the Arabidopsis Puf proteins as fluorescent protein fusions revealed a dynamic, punctate cytoplasmic pattern of localization for most of these proteins. The presence of predicted nuclear export signals and accumulation of AtPuf proteins in the nucleus after treatment of cells with leptomycin B demonstrated that shuttling of these proteins between the cytosol and nucleus is common among these proteins. In addition to the cytoplasmically enriched AtPum proteins, two AtPum proteins showed nuclear targeting with enrichment in the nucleolus. CONCLUSIONS The Puf family of RNA-binding proteins in plants consists of a greater number of members than any other model species studied to date. This, along with the amino acid variability observed within their PUM-HDs, suggests that these proteins may be involved in a wide range of post-transcriptional regulatory events that are important in providing plants with the ability to respond rapidly to changes in environmental conditions and throughout development.
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Affiliation(s)
- Patrick PC Tam
- Department of Biological Sciences, University of Calgary, 2500 University Dr NW Calgary, AB T2N 1N4, Canada
| | - Isabelle H Barrette-Ng
- Department of Biological Sciences, University of Calgary, 2500 University Dr NW Calgary, AB T2N 1N4, Canada
| | - Dawn M Simon
- Department of Biological Sciences, University of Calgary, 2500 University Dr NW Calgary, AB T2N 1N4, Canada
- Department of Biology, University of Nebraska at Kearney, 905 W 25th Street, Kearney, NE 68849, USA
| | - Michael WC Tam
- Department of Biological Sciences, University of Calgary, 2500 University Dr NW Calgary, AB T2N 1N4, Canada
| | - Amanda L Ang
- Department of Biological Sciences, University of Calgary, 2500 University Dr NW Calgary, AB T2N 1N4, Canada
| | - Douglas G Muench
- Department of Biological Sciences, University of Calgary, 2500 University Dr NW Calgary, AB T2N 1N4, Canada
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Racher H, Hansen D. Translational control in the C. elegans hermaphrodite germ line. Genome 2010; 53:83-102. [DOI: 10.1139/g09-090] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The formation of a fully developed gamete from an undifferentiated germ cell requires progression through numerous developmental stages and cell fate decisions. The precise timing and level of gene expression guides cells through these stages. Translational regulation is highly utilized in the germ line of many species, including Caenorhabditis elegans , to regulate gene expression and ensure the proper formation of gametes. In this review, we discuss some of the developmental stages and cell fate decisions involved in the formation of functional gametes in the C. elegans germ line in which translational control has been implicated. These stages include the mitosis versus meiosis decision, the sperm/oocyte decision, and gamete maturation. We also discuss some of the techniques used to identify mRNA targets; the identification of these targets is necessary to clearly understand the role each RNA-binding protein plays in these decisions. Relatively few mRNA targets have been identified, thus providing a major focus for future research. Finally, we propose some reasons why translational control may be utilized so heavily in the germ line. Given that many species have this substantial reliance on translational regulation for the control of gene expression in the germ line, an understanding of translational regulation in the C. elegans germ line is likely to increase our understanding of gamete formation in general.
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Affiliation(s)
- Hilary Racher
- University of Calgary, 2500 University Drive, Department of Biological Sciences, Calgary, AB T2N 1N4, Canada
| | - Dave Hansen
- University of Calgary, 2500 University Drive, Department of Biological Sciences, Calgary, AB T2N 1N4, Canada
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Wurster SE, Maher LJ. Selections that optimize RNA display in the yeast three-hybrid system. RNA (NEW YORK, N.Y.) 2010; 16:253-8. [PMID: 20008486 PMCID: PMC2811653 DOI: 10.1261/rna.1880410] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The yeast three-hybrid system (Y3H) is a powerful tool to select or confirm RNA-protein interactions. Target protein recognition of an RNA insert within a test transcript depends on at least three factors: intrinsic protein affinity for the properly folded insert, retention of RNA insert tertiary structure within a longer RNA transcript, and accessibility of the RNA insert to the target protein. Y3H reporter gene readout reflects the combination of these factors. Here, we discuss RNA insert tertiary structure and accessibility in the Y3H as "RNA display." We review evidence that RNA display can sometimes be optimized during Y3H selections that do not increase the intrinsic affinity of an RNA insert for a target protein. This situation is more likely when a library of RNA inserts and heterogeneous flanking sequences is subjected to selection, and is less likely when point mutations are targeted to the insert in a fixed context. An RNA display vector with enhanced modularity has been developed to minimize sequence context effects in the Y3H.
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Affiliation(s)
- Susan E Wurster
- Department of Biochemistry and Molecular Biology, College of Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA
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Sleumer MC, Mah AK, Baillie DL, Jones SJM. Conserved elements associated with ribosomal genes and their trans-splice acceptor sites in Caenorhabditis elegans. Nucleic Acids Res 2010; 38:2990-3004. [PMID: 20100800 PMCID: PMC2875031 DOI: 10.1093/nar/gkq003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The recent publication of the Caenorhabditis elegans cisRED database has provided an extensive catalog of upstream elements that are conserved between nematode genomes. We have performed a secondary analysis to determine which subsequences of the cisRED motifs are found in multiple locations throughout the C. elegans genome. We used the word-counting motif discovery algorithm DME to form the motifs into groups based on sequence similarity. We then examined the genes associated with each motif group using DAVID and Ontologizer to determine which groups are associated with genes that also have significant functional associations in the Gene Ontology and other gene annotation sources. Of the 3265 motif groups formed, 612 (19%) had significant functional associations with respect to GO terms. Eight of the first 20 motif groups based on frequent dodecamers among the cisRED motif sequences were specifically associated with ribosomal protein genes; two of these were similar to mouse EBP-45, rat HNF3-family and Drosophila Zeste transcription factor binding sites. Additionally, seven motif groups were extensions of the canonical C. elegans trans-splice acceptor site. One motif group was tested for regulatory function in a series of green fluorescent protein expression experiments and was shown to be involved in pharyngeal expression.
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Affiliation(s)
- Monica C Sleumer
- Canada's Michael Smith Genome Sciences Centre, BC Cancer Agency, 570 W 7th Ave Suite 100, Vancouver, BC, Canada
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A 5' cytosine binding pocket in Puf3p specifies regulation of mitochondrial mRNAs. Proc Natl Acad Sci U S A 2009; 106:20192-7. [PMID: 19918084 DOI: 10.1073/pnas.0812079106] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A single regulatory protein can control the fate of many mRNAs with related functions. The Puf3 protein of Saccharomyces cerevisiae is exemplary, as it binds and regulates more than 100 mRNAs that encode proteins with mitochondrial function. Here we elucidate the structural basis of that specificity. To do so, we explore the crystal structures of Puf3p complexes with 2 cognate RNAs. The key determinant of Puf3p specificity is an unusual interaction between a distinctive pocket of the protein with an RNA base outside the "core" PUF-binding site. That interaction dramatically affects binding affinity in vitro and is required for regulation in vivo. The Puf3p structures, combined with those of Puf4p in the same organism, illuminate the structural basis of natural PUF-RNA networks. Yeast Puf3p binds its own RNAs because they possess a -2C and is excluded from those of Puf4p which contain an additional nucleotide in the core-binding site.
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RNA recognition by the embryonic cell fate determinant and germline totipotency factor MEX-3. Proc Natl Acad Sci U S A 2009; 106:20252-7. [PMID: 19915141 DOI: 10.1073/pnas.0907916106] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Totipotent stem cells have the potential to differentiate into every cell type. Renewal of totipotent stem cells in the germline and cellular differentiation during early embryogenesis rely upon posttranscriptional regulatory mechanisms. The Caenorhabditis elegans RNA binding protein, MEX-3, plays a key role in both processes. MEX-3 is a maternally-supplied factor that controls the RNA metabolism of transcripts encoding critical cell fate determinants. However, the nucleotide sequence specificity and requirements of MEX-3 mRNA recognition remain unclear. Only a few candidate regulatory targets have been identified, and the full extent of the network of MEX-3 targets is not known. Here, we define the consensus sequence required for MEX-3 RNA recognition and demonstrate that this element is required for MEX-3 dependent regulation of gene expression in live worms. Based on this work, we identify several candidate MEX-3 targets that help explain its dual role in regulating germline stem cell totipotency and embryonic cell fate specification.
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Structural basis for specific recognition of multiple mRNA targets by a PUF regulatory protein. Proc Natl Acad Sci U S A 2009; 106:20186-91. [PMID: 19901328 DOI: 10.1073/pnas.0812076106] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Caenorhabditis elegans fem-3 binding factor (FBF) is a founding member of the PUMILIO/FBF (PUF) family of mRNA regulatory proteins. It regulates multiple mRNAs critical for stem cell maintenance and germline development. Here, we report crystal structures of FBF in complex with 6 different 9-nt RNA sequences, including elements from 4 natural mRNAs. These structures reveal that FBF binds to conserved bases at positions 1-3 and 7-8. The key specificity determinant of FBF vs. other PUF proteins lies in positions 4-6. In FBF/RNA complexes, these bases stack directly with one another and turn away from the RNA-binding surface. A short region of FBF is sufficient to impart its unique specificity and lies directly opposite the flipped bases. We suggest that this region imposes a flattened curvature on the protein; hence, the requirement for the additional nucleotide. The principles of FBF/RNA recognition suggest a general mechanism by which PUF proteins recognize distinct families of RNAs yet exploit very nearly identical atomic contacts in doing so.
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Francischini CW, Quaggio RB. Molecular characterization of Arabidopsis thaliana PUF proteins - binding specificity and target candidates. FEBS J 2009; 276:5456-70. [DOI: 10.1111/j.1742-4658.2009.07230.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Koh YY, Opperman L, Stumpf C, Mandan A, Keles S, Wickens M. A single C. elegans PUF protein binds RNA in multiple modes. RNA (NEW YORK, N.Y.) 2009; 15:1090-9. [PMID: 19369425 PMCID: PMC2685523 DOI: 10.1261/rna.1545309] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
PUF proteins specifically bind mRNAs to regulate their stability and translation. Here we focus on the RNA-binding specificity of a C. elegans PUF protein, PUF-11. Our findings reveal that PUF-11 binds RNA in multiple modes, in which the protein can accommodate variable spacings between two distinct recognition elements. We propose a structural model in which flexibility in the central region of the protein enables the protein to adopt at least two distinct structures, one of which results in base flipping.
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Affiliation(s)
- Yvonne Yiling Koh
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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Lu G, Dolgner SJ, Hall TMT. Understanding and engineering RNA sequence specificity of PUF proteins. Curr Opin Struct Biol 2009; 19:110-5. [PMID: 19186050 DOI: 10.1016/j.sbi.2008.12.009] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2008] [Accepted: 12/20/2008] [Indexed: 02/02/2023]
Abstract
PUF proteins are RNA-binding proteins named for founding members PUMILIO and fem-3 binding factor (FBF). Together these proteins represent the range of known RNA recognition properties. PUMILIO is a prototypical PUF protein whose RNA sequence specificity is simple, elegant, and predictable. FBF displays differences in RNA recognition that represent divergence from the prototype. Here we review recent studies that examine the engineering of sequence specificity of PUF proteins and its applications as well as studies that increase our understanding of the natural diversity of RNA recognition by this family of proteins.
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Affiliation(s)
- Gang Lu
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, United States of America.
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Stumpf CR, Opperman L, Wickens M. Chapter 14. Analysis of RNA-protein interactions using a yeast three-hybrid system. Methods Enzymol 2008; 449:295-315. [PMID: 19215764 DOI: 10.1016/s0076-6879(08)02414-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
RNA-protein interactions play an essential role in the maturation and regulation of RNAs within eukaryotic organisms. The three-hybrid system provides a simple, yet powerful means to study RNA-protein interactions within the eukaryote Saccharomyces cerevisiae. This chapter describes the basis of the system and applications in both examining specific RNA-protein interactions and screening libraries for novel interactions. We provide a detailed discussion on affinity versus reporter output, variations on library screening (e.g., randomization studies), some adaptations of the system, and updated reagents and protocols.
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Affiliation(s)
- Craig R Stumpf
- Program in Cellular and Molecular Biology, University of Wisconsin-Madison, Madison, Wisconsin, USA
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