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Shi DL. Interplay of RNA-binding proteins controls germ cell development in zebrafish. J Genet Genomics 2024:S1673-8527(24)00163-2. [PMID: 38969260 DOI: 10.1016/j.jgg.2024.06.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Revised: 06/26/2024] [Accepted: 06/27/2024] [Indexed: 07/07/2024]
Abstract
The specification of germ cells in zebrafish mostly relies on an inherited mechanism by which localized maternal determinants, called germ plasm, confer germline fate in the early embryo. Extensive studies have partially allowed the identification of key regulators governing germ plasm formation and subsequent germ cell development. RNA-binding proteins, acting in concert with other germ plasm components, play essential roles in the organization of the germ plasm and the specification, migration, maintenance, and differentiation of primordial germ cells. The loss of their functions impairs germ cell formation and causes sterility or sexual conversion. Evidence is emerging that they instruct germline development through differential regulation of mRNA fates in somatic and germ cells. However, the challenge remains to decipher the complex interplay of maternal germ plasm components in germ plasm compartmentalization and germ cell specification. Since failure to control the developmental outcome of germ cells disrupts the formation of gametes, it is important to gain a complete picture of regulatory mechanisms operating in the germ cell lineage. This review sheds light on the contributions of RNA-binding proteins to germ cell development in zebrafish and highlights intriguing questions that remain open for future investigation.
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Affiliation(s)
- De-Li Shi
- Laboratory of Developmental Biology, CNRS-UMR7622, Institut de Biologie Paris-Seine (IBPS), Sorbonne University, 75005 Paris, France.
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Gajjar G, Huggins HP, Kim ES, Huang W, Bonnet FX, Updike DL, Keiper BD. Two germ granule eIF4E isoforms reside in different mRNPs to hand off C elegans mRNAs from translational repression to activation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.24.595216. [PMID: 38826235 PMCID: PMC11142241 DOI: 10.1101/2024.05.24.595216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
We studied the function of translation factor eIF4E isoforms in regulating mRNAs in germ cell granules/condensates. Translational control of mRNAs plays an essential role in germ cell gene regulation. Messenger ribonucleoprotein (mRNP) complexes assemble on mRNAs as they move from the nucleus into perinuclear germ granules to exert both positive and negative post-transcriptional regulation in the cytoplasm. In C. elegans , germ granules are surprisingly dynamic mRNP condensates that remodel during development. Two eIF4E isoforms (called IFE-1 and IFE-3), eIF4E-Interacting Proteins (4EIPs), RBPs, DEAD-box helicases, polyadenylated mRNAs, Argonautes and miRNAs all occupy positions in germ granules. Affinity purification of IFE-1 and IFE-3 allowed mass spectrometry and mRNA-Seq to identify the proteins and mRNAs that populate stable eIF4E mRNPs. We find translationally controlled mRNAs (e.g. pos-1, mex-3, spn-4, etc.) enriched in IFE-3 mRNPs, but excluded from IFE-1 mRNPs. These mRNAs also require IFE-1 for efficient translation. The findings support a model in which oocytes and embryos utilize the two eIF4Es for opposite purposes on critically regulated germline mRNAs. Careful colocalization of the eIF4Es with other germ granule components suggests an architecture in which GLH-1, PGL-1 and the IFEs are stratified to facilitate sequential interactions for mRNAs. Biochemical characterization demonstrates opposing yet cooperative roles for IFE-3 and IFE-1 to hand-off of translationally controlled mRNAs from the repressed to the activated state, respectively. The model involves eIF4E mRNPs shuttling mRNAs through nuclear pore-associated granules/condensates to cytoplasmic ribosomes.
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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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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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