scholarly journals A widely employed germ cell marker is an ancient disordered protein with reproductive functions in diverse eukaryotes

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Michelle A Carmell ◽  
Gregoriy A Dokshin ◽  
Helen Skaletsky ◽  
Yueh-Chiang Hu ◽  
Josien C van Wolfswinkel ◽  
...  
Keyword(s):  
Germ Cell ◽  
Nuclear Antigen ◽  
Cell Marker ◽  
Eukaryotic Evolution ◽  
C Elegans ◽  
Intrinsically Disordered ◽  
Disordered Protein ◽  
Damage Repair ◽  
Intrinsically Disordered Region ◽  
Multicellular Organisms

The advent of sexual reproduction and the evolution of a dedicated germline in multicellular organisms are critical landmarks in eukaryotic evolution. We report an ancient family of GCNA (germ cell nuclear antigen) proteins that arose in the earliest eukaryotes, and feature a rapidly evolving intrinsically disordered region (IDR). Phylogenetic analysis reveals that GCNA proteins emerged before the major eukaryotic lineages diverged; GCNA predates the origin of a dedicated germline by a billion years. Gcna gene expression is enriched in reproductive cells across eukarya – either just prior to or during meiosis in single-celled eukaryotes, and in stem cells and germ cells of diverse multicellular animals. Studies of Gcna-mutant C. elegans and mice indicate that GCNA has functioned in reproduction for at least 600 million years. Homology to IDR-containing proteins implicated in DNA damage repair suggests that GCNA proteins may protect the genomic integrity of cells carrying a heritable genome.

scholarly journals Author response: A widely employed germ cell marker is an ancient disordered protein with reproductive functions in diverse eukaryotes

2016 ◽  
Author(s):  
Michelle A Carmell ◽  
Gregoriy A Dokshin ◽  
Helen Skaletsky ◽  
Yueh-Chiang Hu ◽  
Josien C van Wolfswinkel ◽  
...  
Keyword(s):  
Germ Cell ◽  
Author Response ◽  
Cell Marker ◽  
Disordered Protein

scholarly journals Protein-based condensation mechanisms drive the assembly of RNA-rich P granules

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Helen Schmidt ◽  
Andrea Putnam ◽  
Dominique Rasoloson ◽  
Geraldine Seydoux
Keyword(s):  
Intrinsically Disordered Protein ◽  
P Granules ◽  
C Elegans ◽  
Intrinsically Disordered ◽  
Disordered Protein ◽  
The Core ◽  
C Terminus ◽  
Germ Granules

Germ granules are protein-RNA condensates that segregate with the embryonic germline. In C. elegans embryos, germ (P) granule assembly requires MEG-3, an intrinsically-disordered protein that forms RNA-rich condensates on the surface of PGL condensates at the core of P granules. MEG-3 is related to the GCNA family and contains an N-terminal disordered region (IDR) and a predicted ordered C-terminus featuring an HMG-like motif (HMGL). We find that MEG-3 is modular protein that uses its IDR to bind RNA and its C-terminus to drive condensation. The HMGL motif mediates binding to PGL-3 and is required for co-assembly of MEG-3 and PGL-3 condensates in vivo. Mutations in HMGL cause MEG-3 and PGL-3 to form separate condensates that no longer co-segregate to the germline or recruit RNA. Our findings highlight the importance of protein-based condensation mechanisms and condensate-condensate interactions in the assembly of RNA-rich germ granules.

scholarly journals PhosIDP: a web tool to visualize the location of phosphorylation sites in disordered regions

2021 ◽  
Author(s):  
Sonia T. Nicolaou ◽  
Max Hebditch ◽  
Owen J. Jonathan ◽  
Chandra S. Verma ◽  
Jim Warwicker
Keyword(s):  
Protein Domains ◽  
Intrinsically Disordered Protein ◽  
Phosphorylation Sites ◽  
Web Tool ◽  
Functional Interpretation ◽  
Intrinsically Disordered ◽  
Disordered Protein ◽  
Intrinsically Disordered Region ◽  
Condensate Formation ◽  
The Web

AbstractCharge is a key determinant of intrinsically disordered protein (IDP) and intrinsically disordered region (IDR) properties. IDPs and IDRs are enriched in sites of phosphorylation, which alters charge. Visualizing the degree to which phosphorylation modulates the charge profile of a sequence would assist in the functional interpretation of IDPs and IDRs. PhosIDP is a web tool that shows variation of charge and fold propensity upon phosphorylation. In combination with the displayed location of protein domains, the information provided by the web tool can lead to functional inferences for the consequences of phosphorylation. IDRs are components of many proteins that form biological condensates. It is shown that IDR charge, and its modulation by phosphorylation, is more tightly controlled for proteins that are essential for condensate formation than for those present in condensates but inessential.

scholarly journals Coordination of RNA and protein condensation by the P granule protein MEG-3

2020 ◽  
Author(s):  
Helen Schmidt ◽  
Andrea Putnam ◽  
Dominique Rasoloson ◽  
Geraldine Seydoux
Keyword(s):  
Protein Interactions ◽  
Intrinsically Disordered Protein ◽  
Protein Protein Interactions ◽  
C Elegans ◽  
Intrinsically Disordered ◽  
Disordered Protein ◽  
C Terminus ◽  
Necessary And Sufficient

ABSTRACTGerm granules are RNA-protein condensates in germ cells. The mechanisms that drive germ granule assembly are not fully understood. MEG-3 is an intrinsically-disordered protein required for germ (P) granule assembly in C. elegans. MEG-3 forms gel-like condensates on liquid condensates assembled by PGL proteins. MEG-3 is related to the GCNA family and contains an N-terminal disordered region (IDR) and a predicted ordered C-terminus featuring an HMG-like motif (HMGL). Using in vitro and in vivo experiments, we find the MEG-3 C-terminus is necessary and sufficient to build MEG-3/PGL co-condensates independent of RNA. The HMGL domain is required for high affinity MEG-3/PGL binding in vitro and for assembly of MEG-3/PGL co-condensates in vivo. The MEG-3 IDR binds RNA in vitro and is required but not sufficient to recruit RNA to P granules. Our findings suggest that P granule assembly depends in part on protein-protein interactions that drive condensation independent of RNA.

scholarly journals The intrinsically disordered protein SPE-18 promotes localized assembly of the major sperm protein in C. elegans spermatocytes

2020 ◽  
Author(s):  
Kari L. Price ◽  
Marc Presler ◽  
Christopher M. Uyehara ◽  
Diane C. Shakes
Keyword(s):  
Intrinsically Disordered Proteins ◽  
Intrinsically Disordered Protein ◽  
Disordered Proteins ◽  
Major Sperm Protein ◽  
Sperm Protein ◽  
C Elegans ◽  
Intrinsically Disordered ◽  
Disordered Protein ◽  
Changing Patterns ◽  
Cytoskeletal Elements

ABSTRACTMany specialized cells use unconventional strategies of cytoskeletal control. Nematode spermatocytes discard their actin and tubulin following meiosis, and instead employ the regulated assembly/disassembly of the Major Sperm Protein (MSP) to drive sperm motility. However prior to the meiotic divisions, MSP is effectively sequestered as it exclusively assembles into paracrystalline structures called fibrous bodies (FBs). The accessory proteins that direct this sequestration process have remained mysterious. This study reveals SPE-18 as an intrinsically disordered protein that that is essential for MSP assembly within FBs. In spe-18 mutant spermatocytes, MSP remains cytosolic, and the cells arrest in meiosis. In wildtype spermatocytes, SPE-18 localizes to pre-FB complexes and functions with the kinase SPE-6 to recruit MSP. Changing patterns of SPE-18 localization revealed unappreciated complexities in FB maturation. Later, within newly individualized spermatids, SPE −18 is rapidly lost, yet SPE-18 loss alone is insufficient for MSP disassembly. Our findings reveal an alternative strategy for sequestering cytoskeletal elements, not as monomers but in localized, bundled polymers. Additionally, these studies provide an important example of disordered proteins promoting ordered cellular structures.Summary StatementIntrinsically disordered proteins are increasingly recognized as key regulators of localized cytoskeletal assembly. Expanding that paradigm, SPE-18 localizes MSP assembly within C. elegans spermatocytes.

scholarly journals A membrane-associated condensate drives paternal epigenetic inheritance in C. elegans

2020 ◽  
Author(s):  
Jan Schreier ◽  
Sabrina Dietz ◽  
Antonio M. de Jesus Domingues ◽  
Ann-Sophie Seistrup ◽  
Dieu An H. Nguyen ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Small Rnas ◽  
Maternal Inheritance ◽  
Epigenetic Inheritance ◽  
C Elegans ◽  
Intrinsically Disordered ◽  
Regulatory Information ◽  
Intrinsically Disordered Region ◽  
Gene Regulatory ◽  
Non Coding Rnas

SUMMARYTransgenerational epigenetic inheritance (TEI) describes the transmission of gene-regulatory information across generations without altering DNA sequences, and allows priming of offspring towards transposable elements (TEs) and changing environmental conditions. One important mechanism that acts in TEI is based on small non-coding RNAs. Whereas factors for maternal inheritance of small RNAs have been identified, paternal inheritance is poorly understood, as much of the cellular content is extruded during spermatogenesis. We identify a phase separation-based mechanism, driven by the protein PEI-1, which is characterized by a BTB-BACK domain and an intrinsically disordered region (IDR). PEI-1 specifically secures the Argonaute protein WAGO-3 within maturing sperm in C. elegans. Localization of PEI granules in mature sperm is coupled, via S-palmitoylation, to myosin-driven transport of membranous organelles. pei-1-like genes are also found in human and often expressed in testis, suggesting that the here identified mechanism may be broadly conserved.

scholarly journals Spatial patterning of P granules by RNA-induced phase separation of the intrinsically-disordered protein MEG-3

2016 ◽  
Author(s):  
Jarrett Smith ◽  
Deepika Calidas ◽  
Helen Schmidt ◽  
Tu Lu ◽  
Dominique Rasoloson ◽  
...  
Keyword(s):  
Phase Separation ◽  
Rna Binding ◽  
Intrinsically Disordered Protein ◽  
P Granules ◽  
C Elegans ◽  
Rna Granules ◽  
Intrinsically Disordered ◽  
Disordered Protein

ABSTRACTRNA granules are non-membrane bound cellular compartments that contain RNA and RNA binding proteins. The molecular mechanisms that regulate the spatial distribution of RNA granules in cells are poorly understood. During polarization of the C. elegans zygote, germline RNA granules, called P granules, assemble preferentially in the posterior cytoplasm. We present evidence that P granule asymmetry depends on RNA-induced phase separation of the granule scaffold MEG-3. MEG-3 is an intrinsically disordered protein that binds and phase separates with RNA in vitro. In vivo, MEG-3 forms a posterior-rich concentration gradient that is anti-correlated with a gradient in the RNA-binding protein MEX-5. MEX-5 is necessary and sufficient to suppress MEG-3 granule formation in vivo, and suppresses RNA-induced MEG-3 phase separation in vitro. Our findings support a model whereby MEX-5 functions as an mRNA sink to locally suppress MEG-3 phase separation and drive P granule asymmetry.HIGHLIGHTS- The intrinsically-disordered protein MEG-3 is essential for localized assembly of P granules in C. elegans zygotes.- MEG-3 binds RNA and RNA stimulates MEG-3 phase separation.- The RNA-binding protein MEX-5 inhibits MEG-3 granule assembly in the anterior cytoplasm by sequestering RNA.

Sign in / Sign up

Export Citation Format

Share Document