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Qiu C, Crittenden SL, Carrick BH, Dillard LB, Costa Dos Santos SJ, Dandey VP, Dutcher RC, Viverette EG, Wine RN, Woodworth J, Campbell ZT, Wickens M, Borgnia MJ, Kimble J, Tanaka Hall TM. A higher order PUF complex is central to regulation of C. elegans germline stem cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.14.599074. [PMID: 38915480 PMCID: PMC11195197 DOI: 10.1101/2024.06.14.599074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
PUF RNA-binding proteins are broadly conserved stem cell regulators. Nematode PUF proteins maintain germline stem cells (GSCs) and, with key partner proteins, repress differentiation mRNAs, including gld-1. Here we report that PUF protein FBF-2 and its partner LST-1 form a ternary complex that represses gld-1 via a pair of adjacent FBF-2 binding elements (FBEs) in its 3ÚTR. One LST-1 molecule links two FBF-2 molecules via motifs in the LST-1 intrinsically-disordered region; the gld-1 FBE pair includes a well-established 'canonical' FBE and a newly-identified noncanonical FBE. Remarkably, this FBE pair drives both full RNA repression in GSCs and full RNA activation upon differentiation. Discovery of the LST-1-FBF-2 ternary complex, the gld-1 adjacent FBEs, and their in vivo significance predicts an expanded regulatory repertoire of different assemblies of PUF-partner complexes in nematode germline stem cells. It also suggests analogous PUF controls may await discovery in other biological contexts and organisms.
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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 27709, USA
| | | | - Brian H. Carrick
- Department of Biochemistry, University of Wisconsin, Madison, WI 53706, USA
- Current address: MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
| | - Lucas B. Dillard
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
- Current address: Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Stephany J. Costa Dos Santos
- Department of Biochemistry, University of Wisconsin, Madison, WI 53706, USA
- These authors contributed equally to the manuscript and are listed in alphabetical order
| | - Venkata P. Dandey
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
- These authors contributed equally to the manuscript and are listed in alphabetical order
| | - Robert C. Dutcher
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
- These authors contributed equally to the manuscript and are listed in alphabetical order
| | - Elizabeth G. Viverette
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
- These authors contributed equally to the manuscript and are listed in alphabetical order
- Current address: Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Robert N. Wine
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
- These authors contributed equally to the manuscript and are listed in alphabetical order
| | - Jennifer Woodworth
- Department of Biochemistry, University of Wisconsin, Madison, WI 53706, USA
- These authors contributed equally to the manuscript and are listed in alphabetical order
| | - Zachary T. Campbell
- Department of Anesthesiology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53792, USA
| | - Marvin Wickens
- Department of Biochemistry, University of Wisconsin, Madison, WI 53706, USA
| | - Mario J. Borgnia
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Judith Kimble
- Department of Biochemistry, University of Wisconsin, Madison, WI 53706, 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 27709, USA
- Lead contact
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2
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Carrick BH, Crittenden SL, Chen F, Linsley M, Woodworth J, Kroll-Conner P, Ferdous AS, Keleş S, Wickens M, Kimble J. PUF partner interactions at a conserved interface shape the RNA-binding landscape and cell fate in Caenorhabditis elegans. Dev Cell 2024; 59:661-675.e7. [PMID: 38290520 PMCID: PMC11253550 DOI: 10.1016/j.devcel.2024.01.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 11/10/2023] [Accepted: 01/08/2024] [Indexed: 02/01/2024]
Abstract
Protein-RNA regulatory networks underpin much of biology. C. elegans FBF-2, a PUF-RNA-binding protein, binds over 1,000 RNAs to govern stem cells and differentiation. FBF-2 interacts with multiple protein partners via a key tyrosine, Y479. Here, we investigate the in vivo significance of partnerships using a Y479A mutant. Occupancy of the Y479A mutant protein increases or decreases at specific sites across the transcriptome, varying with RNAs. Germline development also changes in a specific fashion: Y479A abolishes one FBF-2 function-the sperm-to-oocyte cell fate switch. Y479A's effects on the regulation of one mRNA, gld-1, are critical to this fate change, though other network changes are also important. FBF-2 switches from repression to activation of gld-1 RNA, likely by distinct FBF-2 partnerships. The role of RNA-binding protein partnerships in governing RNA regulatory networks will likely extend broadly, as such partnerships pervade RNA controls in virtually all metazoan tissues and species.
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Affiliation(s)
- Brian H Carrick
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA.
| | - Sarah L Crittenden
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Fan Chen
- Department of Statistics, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - MaryGrace Linsley
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Jennifer Woodworth
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Peggy Kroll-Conner
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Ahlan S Ferdous
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Sündüz Keleş
- Department of Statistics, University of Wisconsin-Madison, Madison, WI 53706, USA; Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Marvin Wickens
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA.
| | - Judith Kimble
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA.
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3
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Smith PR, Campbell ZT. RNA-binding proteins in pain. WILEY INTERDISCIPLINARY REVIEWS. RNA 2024; 15:e1843. [PMID: 38576117 PMCID: PMC11003723 DOI: 10.1002/wrna.1843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 03/13/2024] [Accepted: 03/14/2024] [Indexed: 04/06/2024]
Abstract
RNAs are meticulously controlled by proteins. Through direct and indirect associations, every facet in the brief life of an mRNA is subject to regulation. RNA-binding proteins (RBPs) permeate biology. Here, we focus on their roles in pain. Chronic pain is among the largest challenges facing medicine and requires new strategies. Mounting pharmacologic and genetic evidence obtained in pre-clinical models suggests fundamental roles for a broad array of RBPs. We describe their diverse roles that span RNA modification, splicing, stability, translation, and decay. Finally, we highlight opportunities to expand our understanding of regulatory interactions that contribute to pain signaling. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications Translation > Regulation RNA in Disease and Development > RNA in Disease.
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Affiliation(s)
- Patrick R. Smith
- Department of Anaesthesiology, University of Wisconsin-Madison, Madison, WI, USA 53792
| | - Zachary T. Campbell
- Department of Anaesthesiology, University of Wisconsin-Madison, Madison, WI, USA 53792
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA 53792
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4
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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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5
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Ferdous AS, Costa Dos Santos SJ, Kanzler CR, Shin H, Carrick BH, Crittenden SL, Wickens M, Kimble J. The in vivo functional significance of PUF hub partnerships in C. elegans germline stem cells. Development 2023; 150:dev201705. [PMID: 37070766 PMCID: PMC10259659 DOI: 10.1242/dev.201705] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 03/29/2023] [Indexed: 04/19/2023]
Abstract
PUF RNA-binding proteins are conserved stem cell regulators. Four PUF proteins govern self-renewal of Caenorhabditis elegans germline stem cells together with two intrinsically disordered proteins, LST-1 and SYGL-1. Based on yeast two-hybrid results, we previously proposed a composite self-renewal hub in the stem cell regulatory network, with eight PUF partnerships and extensive redundancy. Here, we investigate LST-1-PUF and SYGL-1-PUF partnerships and their molecular activities in their natural context - nematode stem cells. We confirm LST-1-PUF partnerships and their specificity to self-renewal PUFs by co-immunoprecipitation and show that an LST-1(AmBm) mutant defective for PUF-interacting motifs does not complex with PUFs in nematodes. LST-1(AmBm) is used to explore the in vivo functional significance of the LST-1-PUF partnership. Tethered LST-1 requires this partnership to repress expression of a reporter RNA, and LST-1 requires the partnership to co-immunoprecipitate with NTL-1/Not1 of the CCR4-NOT complex. We suggest that the partnership provides multiple molecular interactions that work together to form an effector complex on PUF target RNAs in vivo. Comparison of LST-1-PUF and Nanos-Pumilio reveals fundamental molecular differences, making LST-1-PUF a distinct paradigm for PUF partnerships.
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Affiliation(s)
- Ahlan S. Ferdous
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | | | - Charlotte R. Kanzler
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Heaji Shin
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Brian H. Carrick
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Sarah L. Crittenden
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Marvin Wickens
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Judith Kimble
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
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6
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Ferdous AS, Costa Dos Santos SJ, Kanzler CR, Shin H, Carrick BH, Crittenden SL, Wickens M, Kimble J. Functional significance of PUF partnerships in C. elegans germline stem cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.15.528708. [PMID: 36824876 PMCID: PMC9949348 DOI: 10.1101/2023.02.15.528708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/26/2023]
Abstract
PUF RNA-binding proteins are conserved stem cell regulators. Four PUF proteins govern self-renewal of C. elegans germline stem cells together with two intrinsically disordered proteins, LST-1 and SYGL-1. Based on yeast two-hybrid results, we proposed a composite self-renewal hub in the stem cell regulatory network, with eight PUF partnerships and extensive redundancy. Here, we investigate LST-1-PUF and SYGL-1-PUF partnerships and their molecular activities in their natural context - nematode stem cells. We confirm LST-1-PUF partnerships and their specificity to self-renewal PUFs by co-immunoprecipitation and show that an LST-1(A m B m ) mutant defective for PUF-interacting motifs does not complex with PUFs in nematodes. LST-1(A m B m ) is used to explore the functional significance of the LST-1-PUF partnership. Tethered LST-1 requires the partnership to repress expression of a reporter RNA, and LST-1 requires the partnership to co-immunoprecipitate with NTL-1/Not1 of the CCR4-NOT complex. We suggest that the partnership provides multiple molecular interactions that work together to form an effector complex on PUF target RNAs. Comparison of PUF-LST-1 and Pumilio-Nanos reveals fundamental molecular differences, making PUF-LST-1 a distinct paradigm for PUF partnerships. Summary statement Partnerships between PUF RNA-binding proteins and intrinsically disordered proteins are essential for stem cell maintenance and RNA repression.
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Affiliation(s)
- Ahlan S Ferdous
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | | | - Charlotte R Kanzler
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Heaji Shin
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Brian H Carrick
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Sarah L Crittenden
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Marvin Wickens
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Judith Kimble
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
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7
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Ellis RE. Sex Determination in Nematode Germ Cells. Sex Dev 2022:1-18. [PMID: 35172320 PMCID: PMC9378769 DOI: 10.1159/000520872] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 11/02/2021] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Animal germ cells differentiate as sperm or as oocytes. These sexual fates are controlled by complex regulatory pathways to ensure that the proper gametes are made at the appropriate times. SUMMARY Nematodes like Caenorhabditis elegans and its close relatives are ideal models for studying how this regulation works, because the XX animals are self-fertile hermaphrodites that produce both sperm and oocytes. In these worms, germ cells use the same signal transduction pathway that functions in somatic cells. This pathway determines the activity of the transcription factor TRA-1, a Gli protein that can repress male genes. However, the pathway is extensively modified in germ cells, largely by the action of translational regulators like the PUF proteins. Many of these modifications play critical roles in allowing the XX hermaphrodites to make sperm in an otherwise female body. Finally, TRA-1 cooperates with chromatin regulators in the germ line to control the activity of fog-1 and fog-3, which are essential for spermatogenesis. FOG-1 and FOG-3 work together to determine germ cell fates by blocking the translation of oogenic transcripts. Key Messages: Although there is great diversity in how germ cell fates are controlled in other animals, many of the key nematode genes are conserved, and the critical role of translational regulators may be universal.
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Affiliation(s)
- Ronald E Ellis
- Department of Molecular Biology, Rowan University SOM, Stratford, New Jersey, USA
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8
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Qiu C, Wine RN, Campbell ZT, Hall T. Bipartite interaction sites differentially modulate RNA-binding affinity of a protein complex essential for germline stem cell self-renewal. Nucleic Acids Res 2022; 50:536-548. [PMID: 34908132 PMCID: PMC8754657 DOI: 10.1093/nar/gkab1220] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 11/23/2021] [Accepted: 12/08/2021] [Indexed: 01/09/2023] Open
Abstract
In C. elegans, PUF proteins promote germline stem cell self-renewal. Their functions hinge on partnerships with two proteins that are redundantly required for stem cell maintenance. Here we focus on understanding how the essential partner protein, LST-1, modulates mRNA regulation by the PUF protein, FBF-2. LST-1 contains two nonidentical sites of interaction with FBF-2, LST-1 A and B. Our crystal structures of complexes of FBF-2, LST-1 A, and RNA visualize how FBF-2 associates with LST-1 A versus LST-1 B. One commonality is that FBF-2 contacts the conserved lysine and leucine side chains in the KxxL motifs in LST-1 A and B. A key difference is that FBF-2 forms unique contacts with regions N- and C-terminal to the KxxL motif. Consequently, LST-1 A does not modulate the RNA-binding affinity of FBF-2, whereas LST-1 B decreases RNA-binding affinity of FBF-2. The N-terminal region of LST-1 B, which binds near the 5' end of RNA elements, is essential to modulate FBF-2 RNA-binding affinity, while the C-terminal residues of LST-1 B contribute strong binding affinity to FBF-2. We conclude that LST-1 has the potential to impact which mRNAs are regulated depending on the precise nature of engagement through its functionally distinct FBF binding sites.
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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 27709, USA
| | - Robert N Wine
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Zachary T Campbell
- Department of Biological Sciences, University of Texas at Dallas, Richardson, TX 75025, 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 27709, USA
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9
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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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10
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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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11
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Haupt KA, Enright AL, Ferdous AS, Kershner AM, Shin H, Wickens M, Kimble J. The molecular basis of LST-1 self-renewal activity and its control of stem cell pool size. Development 2019; 146:dev.181644. [PMID: 31515205 DOI: 10.1242/dev.181644] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 09/05/2019] [Indexed: 01/01/2023]
Abstract
PUF RNA-binding proteins have diverse roles in animal development, with a broadly conserved role in stem cells. Two paradigmatic PUF proteins, FBF-1 and FBF-2, promote both self-renewal and differentiation in the C. elegans germline. The LST-1 protein is a pivotal regulator of self-renewal and is oncogenic when mis-expressed. Here, we demonstrate that LST-1 self-renewal activity resides within a predicted disordered region that harbors two KXXL motifs. We find that the KXXL motifs mediate the binding of LST-1 to FBF, and that point mutations of these motifs abrogate LST-1 self-renewal activity. The LST-1-FBF partnership is therefore crucial to stem cell maintenance and is a key element in the FBF regulatory network. A distinct region within LST-1 determines its spatial expression and size of the GSC pool. Most importantly, the molecular understanding of how an IDR-rich protein works in an essential partnership with a conserved stem cell regulator and RNA-binding protein suggests broad new avenues for combinatorial control.
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Affiliation(s)
- Kimberly A Haupt
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Amy L Enright
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Ahlan S Ferdous
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Aaron M Kershner
- Howard Hughes Medical Institute, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Heaji Shin
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Marvin Wickens
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Judith Kimble
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA .,Howard Hughes Medical Institute, University of Wisconsin-Madison, Madison, WI 53706, USA
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12
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de la Peña JBI, Song JJ, Campbell ZT. RNA control in pain: Blame it on the messenger. WILEY INTERDISCIPLINARY REVIEWS-RNA 2019; 10:e1546. [PMID: 31090211 DOI: 10.1002/wrna.1546] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 04/17/2019] [Accepted: 04/22/2019] [Indexed: 12/12/2022]
Abstract
mRNA function is meticulously controlled. We provide an overview of the integral role that posttranscriptional controls play in the perception of painful stimuli by sensory neurons. These specialized cells, termed nociceptors, precisely regulate mRNA polarity, translation, and stability. A growing body of evidence has revealed that targeted disruption of mRNAs and RNA-binding proteins robustly diminishes pain-associated behaviors. We propose that the use of multiple independent regulatory paradigms facilitates robust temporal and spatial precision of protein expression in response to a range of pain-promoting stimuli. This article is categorized under: RNA in Disease and Development > RNA in Disease Translation > Translation Regulation RNA Turnover and Surveillance > Regulation of RNA Stability.
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Affiliation(s)
- June Bryan I de la Peña
- Department of Biological Sciences and the Center for Advanced Pain Studies, University of Texas, Dallas, Richardson, Texas
| | - Jane J Song
- Department of Biological Sciences and the Center for Advanced Pain Studies, University of Texas, Dallas, Richardson, Texas
| | - Zachary T Campbell
- Department of Biological Sciences and the Center for Advanced Pain Studies, University of Texas, Dallas, Richardson, Texas
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13
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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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14
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Qiu C, Bhat VD, Rajeev S, Zhang C, Lasley AE, Wine RN, Campbell ZT, Hall TMT. A crystal structure of a collaborative RNA regulatory complex reveals mechanisms to refine target specificity. eLife 2019; 8:48968. [PMID: 31397673 PMCID: PMC6697444 DOI: 10.7554/elife.48968] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 08/09/2019] [Indexed: 01/09/2023] Open
Abstract
In the Caenorhabditis elegans germline, fem-3 Binding Factor (FBF) partners with LST-1 to maintain stem cells. A crystal structure of an FBF-2/LST-1/RNA complex revealed that FBF-2 recognizes a short RNA motif different from the characteristic 9-nt FBF binding element, and compact motif recognition coincided with curvature changes in the FBF-2 scaffold. Previously, we engineered FBF-2 to favor recognition of shorter RNA motifs without curvature change (Bhat et al., 2019). In vitro selection of RNAs bound by FBF-2 suggested sequence specificity in the central region of the compact element. This bias, reflected in the crystal structure, was validated in RNA-binding assays. FBF-2 has the intrinsic ability to bind to this shorter motif. LST-1 weakens FBF-2 binding affinity for short and long motifs, which may increase target selectivity. Our findings highlight the role of FBF scaffold flexibility in RNA recognition and suggest a new mechanism by which protein partners refine target site selection.
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Affiliation(s)
- Chen Qiu
- Epigenetics and Stem Cell Biology LaboratoryNational Institute of Environmental Health Sciences, National Institutes of HealthResearch Triangle ParkUnited States
| | - Vandita D Bhat
- Department of Biological SciencesUniversity of Texas at DallasRichardsonUnited States
| | - Sanjana Rajeev
- Department of Biological SciencesUniversity of Texas at DallasRichardsonUnited States
| | - Chi Zhang
- Department of Biological SciencesUniversity of Texas at DallasRichardsonUnited States
| | - Alexa E Lasley
- Department of Biological SciencesUniversity of Texas at DallasRichardsonUnited States
| | - Robert N Wine
- Epigenetics and Stem Cell Biology LaboratoryNational Institute of Environmental Health Sciences, National Institutes of HealthResearch Triangle ParkUnited States
| | - Zachary T Campbell
- Department of Biological SciencesUniversity of Texas at DallasRichardsonUnited States
| | - Traci M Tanaka Hall
- Epigenetics and Stem Cell Biology LaboratoryNational Institute of Environmental Health Sciences, National Institutes of HealthResearch Triangle ParkUnited States
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15
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Shin H, Haupt KA, Kershner AM, Kroll-Conner P, Wickens M, Kimble J. SYGL-1 and LST-1 link niche signaling to PUF RNA repression for stem cell maintenance in Caenorhabditis elegans. PLoS Genet 2017; 13:e1007121. [PMID: 29232700 PMCID: PMC5741267 DOI: 10.1371/journal.pgen.1007121] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 12/22/2017] [Accepted: 11/20/2017] [Indexed: 01/14/2023] Open
Abstract
Central questions in regenerative biology include how stem cells are maintained and how they transition from self-renewal to differentiation. Germline stem cells (GSCs) in Caeno-rhabditis elegans provide a tractable in vivo model to address these questions. In this system, Notch signaling and PUF RNA binding proteins, FBF-1 and FBF-2 (collectively FBF), maintain a pool of GSCs in a naïve state. An open question has been how Notch signaling modulates FBF activity to promote stem cell self-renewal. Here we report that two Notch targets, SYGL-1 and LST-1, link niche signaling to FBF. We find that SYGL-1 and LST-1 proteins are cytoplasmic and normally restricted to the GSC pool region. Increasing the distribution of SYGL-1 expands the pool correspondingly, and vast overexpression of either SYGL-1 or LST-1 generates a germline tumor. Thus, SYGL-1 and LST-1 are each sufficient to drive "stemness" and their spatial restriction prevents tumor formation. Importantly, SYGL-1 and LST-1 can only drive tumor formation when FBF is present. Moreover, both proteins interact physically with FBF, and both are required to repress a signature FBF mRNA target. Together, our results support a model in which SYGL-1 and LST-1 form a repressive complex with FBF that is crucial for stem cell maintenance. We further propose that progression from a naïve stem cell state to a state primed for differentiation relies on loss of SYGL-1 and LST-1, which in turn relieves FBF target RNAs from repression. Broadly, our results provide new insights into the link between niche signaling and a downstream RNA regulatory network and how this circuitry governs the balance between self-renewal and differentiation.
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Affiliation(s)
- Heaji Shin
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Kimberly A. Haupt
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Aaron M. Kershner
- Howard Hughes Medical Institute, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Peggy Kroll-Conner
- Howard Hughes Medical Institute, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Marvin Wickens
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Judith Kimble
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Howard Hughes Medical Institute, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
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16
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Weidmann CA, Qiu C, Arvola RM, Lou TF, Killingsworth J, Campbell ZT, Tanaka Hall TM, Goldstrohm AC. Drosophila Nanos acts as a molecular clamp that modulates the RNA-binding and repression activities of Pumilio. eLife 2016; 5. [PMID: 27482653 PMCID: PMC4995099 DOI: 10.7554/elife.17096] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 08/01/2016] [Indexed: 01/03/2023] Open
Abstract
Collaboration among the multitude of RNA-binding proteins (RBPs) is ubiquitous, yet our understanding of these key regulatory complexes has been limited to single RBPs. We investigated combinatorial translational regulation by Drosophila Pumilio (Pum) and Nanos (Nos), which control development, fertility, and neuronal functions. Our results show how the specificity of one RBP (Pum) is modulated by cooperative RNA recognition with a second RBP (Nos) to synergistically repress mRNAs. Crystal structures of Nos-Pum-RNA complexes reveal that Nos embraces Pum and RNA, contributes sequence-specific contacts, and increases Pum RNA-binding affinity. Nos shifts the recognition sequence and promotes repression complex formation on mRNAs that are not stably bound by Pum alone, explaining the preponderance of sub-optimal Pum sites regulated in vivo. Our results illuminate the molecular mechanism of a regulatory switch controlling crucial gene expression programs, and provide a framework for understanding how the partnering of RBPs evokes changes in binding specificity that underlie regulatory network dynamics. DOI:http://dx.doi.org/10.7554/eLife.17096.001 Molecules of DNA contain the instructions needed to make proteins inside cells. Proteins perform many different roles and each needs to be produced at the right time and in the right amounts to enable the cells to survive. The DNA is first copied to make molecules of ribonucleic acid (RNA), which are then used as templates to make the proteins. One way to control protein production is to regulate the RNA molecules. A family of proteins called RNA-binding proteins can recognise and bind to specific RNA molecules and determine whether a RNA molecule is destroyed, used to produce proteins, or stored for later use. In effect, these RNA-binding proteins act as switches that turn protein production on or off. Nanos and Pumilio are two RNA-binding proteins that are found in many organisms, including humans and other animals. Genetic studies in fruit flies show that these two proteins influence development, the nervous system and the behaviour of stem cells by switching off the production of certain proteins. To investigate how Nanos and Pumilio work together to regulate protein production, Weidmann, Qiu et al. used a variety of techniques to study the activity of these proteins in cells taken from fruit fly embryos. The experiments reveal that Nanos acts like a clamp to hold Pumilio close to specific RNAs, which allows Pumilio to switch off the production of the corresponding proteins. The presence of Nanos allows Pumilio to regulate RNAs that it cannot bind to alone. Therefore, the experiments show that by working together with Nanos, Pumilio is able to regulate a wider variety of RNAs than it would otherwise be able to. These findings provide a molecular understanding for why fruit fly mutants that lack Nanos or Pumilio have severe body defects and reduced fertility. The next challenge is to identify the specific RNAs targeted by Nanos and Pumilio in stem cells, the nervous system and during development. DOI:http://dx.doi.org/10.7554/eLife.17096.002
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Affiliation(s)
- Chase A Weidmann
- Department of Biological Chemistry, University of Michigan, Ann Arbor, United States
| | - Chen Qiu
- Epigenetics and Stem Cell Biology Laboratory, National Institutes of Health, Research Triangle Park, United States.,National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, United States
| | - René M Arvola
- Department of Biological Chemistry, University of Michigan, Ann Arbor, United States
| | - Tzu-Fang Lou
- Department of Biological Sciences, University of Texas at Dallas, Richardson, United States
| | - Jordan Killingsworth
- Department of Biological Chemistry, University of Michigan, Ann Arbor, United States
| | - Zachary T Campbell
- Department of Biological Sciences, University of Texas at Dallas, Richardson, United States
| | - Traci M Tanaka Hall
- Epigenetics and Stem Cell Biology Laboratory, National Institutes of Health, Research Triangle Park, United States.,National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, United States
| | - Aaron C Goldstrohm
- Department of Biological Chemistry, University of Michigan, Ann Arbor, United States.,Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, United States
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17
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Menichelli E, Wu J, Campbell ZT, Wickens M, Williamson JR. Biochemical characterization of the Caenorhabditis elegans FBF.CPB-1 translational regulation complex identifies conserved protein interaction hotspots. J Mol Biol 2012; 425:725-37. [PMID: 23159558 DOI: 10.1016/j.jmb.2012.11.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Revised: 11/01/2012] [Accepted: 11/07/2012] [Indexed: 10/27/2022]
Abstract
Caenorhabditis elegans CPB-1 (cytoplasmic polyadenylation element binding protein homolog-1) and FBF (fem-3 mRNA binding factor) are evolutionary conserved regulators of mRNA translation that belong to the CPEB (cytoplasmic polyadenylation element binding) and PUF (Pumilio and FBF) protein families, respectively. In hermaphrodite worms, CPB-1 and FBF control key steps during germline development, including stem cell maintenance and sex determination. While CPB-1 and FBF are known to interact, the molecular basis and function of the CPB-1⋅FBF complex are not known. The surface of CPB-1 that interacts with FBF was localized using in vivo and in vitro methods to a 10-residue region at the N-terminus of the protein and these residues are present in the FBF-binding protein GLD-3 (germline development defective-3). PUF proteins are characterized by the presence of eight α-helical repeats (PUF repeats) arranged side by side in an elongated structure. Critical residues for CPB-1 binding are found in the extended loop that connects PUF repeats 7 and 8. The same FBF residues also mediate binding to GLD-3, indicating a conserved binding mode between different protein partners. CPB-1 binding was competitive with GLD-3, suggestive of mutual exclusivity in vivo. RNA binding measurements demonstrated that CPB-1 alters the affinity of FBF for specific RNA sequences, implying a functional model where the coregulatory protein CPB-1 modulates FBF target selection.
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Affiliation(s)
- Elena Menichelli
- Department of Molecular Biology, The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
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