The research report should be a detailed narrative explaining the function, biological processes, and localization of the gene product. Citations should be given for all claims.
You should prioritize authoritative reviews and primary scientific literature when conducting research. You can supplement
this with annotations you find in gene/protein databases, but these can be outdated or inaccurate.
We are specifically interested in the primary function of the gene - for enzymes, what reaction is catalyzed, and what is the substrate specificity? For transporters, what is the substrate? For structural proteins or adapters, what is the broader structural role? For signaling molecules, what is the role in the pathway.
We are interested in where in or outside the cell the gene product carries out its function.
We are also interested in the signaling or biochemical pathways in which the gene functions. We are less interested in broad pleiotropic effects, except where these elucidate the precise role.
Include evidence where possible. We are interested in both experimental evidence as well as inference from structure, evolution, or bioinformatic analysis. Precise studies should be prioritized over high-throughput, where available.
The target protein is DEPS-1 (defective P granules and sterile protein deps-1) from Caenorhabditis elegans, encoded by deps-1 / ORF Y65B4BL.2. Spike et al. mapped the phenotype to Y65B4BL.2, showed that RNAi of Y65B4BL.2 phenocopied deps-1 mutants, and detected allele-specific lesions in independent deps-1 alleles, verifying gene identity (spike2008deps1promotespgranule pages 4-5). DEPS-1 is described experimentally as a novel ~69 kDa protein with a serine-rich low-complexity C-terminus, lacking obvious canonical RNA-binding motifs, and conserved in related Caenorhabditis species (spike2008deps1promotespgranule pages 4-5).
P granules are germline-specific ribonucleoprotein condensates (a type of membraneless organelle) that localize to the cytoplasmic face of germline nuclei and concentrate factors involved in post-transcriptional regulation and small-RNA-based genome surveillance. DEPS-1 is a constitutive P-granule component: DEPS-1::GFP is cytoplasmic and enriched on P granules, and anti-DEPS-1 staining of P granules is lost in deps-1 mutants (while nuclear staining persists, consistent with antibody cross-reactivity) (spike2008deps1promotespgranule pages 4-5).
DEPS-1 connects P granules to multiple germline small-RNA pathways, most notably:
- piRNA (21U RNA) pathway: PRG-1 (a PIWI Argonaute) binds 21U RNAs to recognize targets.
- Secondary endo-siRNA (22G RNA) pathways: RdRP-generated 22G RNAs amplify silencing and are associated with mutator machinery.
Mechanistically, DEPS-1 acts primarily downstream of primary piRNA biogenesis, promoting effective piRNA-dependent silencing through effects on secondary 22G RNAs and condensate organization (suen2020deps1isrequired pages 8-9).
Loss-of-function deps-1 mutations disrupt the localization of PGL-1 (and PGL-3) to P granules, consistent with DEPS-1 acting upstream of PGL proteins in a P-granule formation pathway (spike2008deps1promotespgranule pages 4-5). This places DEPS-1 among the structural/organizational factors needed to assemble normal P-granule protein composition.
DEPS-1 is required for normal germline development and fertility, with a maternal-effect and temperature-sensitive sterility phenotype:
- In deps-1(bn121) M−Z− animals raised at 24.5°C, 93% are sterile (spike2008deps1promotespgranule pages 4-5).
- Germlines frequently lack gametes and have reduced germ cell numbers: 56% of germline arms had <200 germ nuclei (n=48), and 63% lacked both sperm and oocytes (spike2008deps1promotespgranule pages 4-5).
- Mean germ cells per gonad arm at 24.5°C: 254 ± 236 (n=16, range 10–762) vs wild-type 586 ± 45 (n=6, range 526–651) (spike2008deps1promotespgranule pages 4-5).
These data support DEPS-1 as a core germline integrity factor, likely through maintaining P-granule-dependent RNA regulation.
Spike et al. provide evidence that DEPS-1 promotes accumulation of rde-4 mRNA and RDE-4 protein, a dsRNA-binding factor essential for RNAi:
- rde-4 mRNA reduced 7–10-fold in deps-1 gravid adults (M−Z−) (spike2008deps1promotespgranule pages 7-8).
- RDE-4 protein reduced by ~10-fold in deps-1 M−Z− adults (spike2008deps1promotespgranule pages 7-8).
Consistent with this, deps-1 mutants are resistant to germline RNAi against maternally expressed genes such as pos-1, skn-1, pie-1, while RNAi against several zygotically expressed targets was not obviously altered (spike2008deps1promotespgranule pages 7-8). This supports a model in which DEPS-1 influences RNAi competence at least partly indirectly via maintaining RDE-4 levels.
Suen et al. show DEPS-1 physically couples the P granule scaffold to PIWI:
- DEPS-1 binds the PRG-1 PIWI domain, mediated by an N-terminal PIWI-binding site (PBS) motif (suen2020deps1isrequired pages 4-5).
- Microscale thermophoresis (MST) binding affinities:
- Full-length PRG-1 vs full-length DEPS-1: Kdapp = 855 ± 133 nM (suen2020deps1isrequired pages 3-4, suen2020deps1isrequired media a9234a31).
- PBS peptide vs PRG-1 PIWI domain: Kdapp = 1.9 µM ± 98 nM (suen2020deps1isrequired pages 3-4, suen2020deps1isrequired media a9234a31).
Deletion of PBS disperses DEPS-1 into the cytoplasm and disrupts higher-order organization of PRG-1/DEPS-1 condensates (suen2020deps1isrequired pages 3-4).
DEPS-1 contributes to condensate morphology and links piRNA recognition to downstream amplification:
- Removing PBS compacts PRG-1 condensates; PRG-1/DEPS-1 normally form intertwining clusters to build elongated perinuclear condensates (suen2020deps1isrequired pages 3-4).
- deps-1 loss or PBS mutation results in fewer, brighter MUT-16 foci and altered PRG-1 condensate properties, consistent with disruption of the interface between P granules and mutator foci (suen2020deps1isrequired pages 9-10).
DEPS-1 is not required for primary piRNA (21U) abundance, but is required for piRNA-dependent silencing through effects on secondary siRNAs:
- In deps-1 mutants, 21U levels remain similar to wild type, while prg-1 mutants show strong loss of 21Us (one-sided t-test p < 10−20, n=2) (suen2020deps1isrequired pages 8-9).
- deps-1 affects secondary 22G siRNAs across pathways, with a strong effect on WAGO-class targets:
- 300/425 WAGO targets show >2-fold reduction in 22Gs (hypergeometric p < 10−139) (suen2020deps1isrequired pages 8-9).
- Limited effect on ERGO-1 targets (7/23, p < 0.2) (suen2020deps1isrequired pages 8-9).
- For CSR-1 class, overlap with strong reductions is limited (e.g., 4/162 CSR-1 targets among genes with >2-fold 22G reduction; hypergeometric p < 10−13) (suen2020deps1isrequired pages 8-9).
- A global statistic reported: 8986/11,088 germline-expressed genes are endo-siRNA targets; 55/63 curated P-granule factors are endo-siRNA targets; and 10/63 P-granule factors show differential 22Gs in deps-1 mutant (suen2020deps1isrequired pages 9-10).
- Correlation between small RNA depletion and mRNA increase: when small RNAs decrease, target mRNAs tend to be upregulated (R² = 0.58; p < 0.01) (suen2020deps1isrequired pages 8-9).
Functionally, deps-1 mutants and PBS-deletion mutants desilence a piRNA sensor transgene, demonstrating a direct impact on piRNA-mediated repression in vivo (suen2020deps1isrequired pages 3-4, suen2020deps1isrequired media a9234a31).
A major recent technical advance directly involving DEPS-1 is the application of pan-protein staining with ~3× expansion microscopy (EExM) to resolve germ-granule subdomains:
- DEPS-1 condensates appear as small protein clusters localized within protein-dense P granules (suen2023expansionmicroscopyreveals pages 11-15).
- Quantitative granule counts per nucleus: 2.5 ± 0.8 (GFP-DEPS-1-positive granules) vs 2.8 ± 1.3 (pan-stain-positive granules), based on 9 nuclei from 3 experiments (suen2023expansionmicroscopyreveals pages 11-15).
- deps-1(bn124) mutants show fewer perinuclear protein-dense structures and can show PRG-1–containing granules dissociated from the nuclear membrane; P granule size is reduced in deps-1 and mut-16 mutants compared with wild type with reported significance (p < 0.001; p < 0.0001*) (suen2023expansionmicroscopyreveals pages 11-15).
This work reinforces the concept that germ granules are not homogeneous droplets but contain spatially organized subdomains, and provides an implementable quantitative pipeline for granule morphology analysis.
A 2024 bioRxiv preprint was retrieved that mentions DEPS-1 in passing in the snippet returned by search; however, in the accessible extracted sections here, no interpretable DEPS-1-specific experimental evidence was available for extraction, so it is not used to support new DEPS-1 claims in this report.
Research groups actively use deps-1 and DEPS-1-based tools to interrogate germline condensates and small-RNA silencing:
1. piRNA sensor transgenes (H2B reporter with a piRNA target site) to assay defects in piRNA silencing; deps-1 null and ΔPBS mutants desilence this sensor (suen2020deps1isrequired pages 3-4, suen2020deps1isrequired media a9234a31).
2. CRISPR/Cas9 motif editing of DEPS-1 (PBS deletion/replacement) to separate “presence in P granules” from “PIWI binding,” enabling causal tests of condensate organization vs silencing output (suen2020deps1isrequired pages 4-5).
3. Quantitative microscopy pipelines (e.g., expansion microscopy with pan-protein staining) for nanoscale mapping of DEPS-1 within perinuclear protein-dense structures and for measuring mutant effects on granule size and nuclear-envelope association (suen2023expansionmicroscopyreveals pages 11-15).
4. Germline RNAi competence assays using feeding RNAi against maternal genes, leveraging the RDE-4 dependency and deps-1-specific RNAi resistance phenotypes (spike2008deps1promotespgranule pages 7-8).
Taken together, the evidence supports annotating DEPS-1 as a non-enzymatic, germline-specific condensate scaffold/adaptor that organizes perinuclear germ granules and couples them to small-RNA effector pathways.
Mechanistically, DEPS-1 appears to provide two separable but linked functions:
1. P-granule assembly/maintenance via upstream effects on PGL protein localization and on accumulation of other P-granule factors (e.g., GLH-1) (spike2008deps1promotespgranule pages 4-5).
2. piRNA pathway coupling via a direct DEPS-1–PRG-1 interaction (PBS–PIWI binding) that supports proper PRG-1 condensate ultrastructure and promotes downstream 22G siRNA amplification required for effective silencing (suen2020deps1isrequired pages 3-4, suen2020deps1isrequired pages 8-9).
A consistent theme is that DEPS-1 loss perturbs both granule composition/architecture and small-RNA output, implying a functional relationship between condensate ultrastructure and biochemical throughput of gene-silencing reactions.
| Finding | Function/process | Localization | Interactions/partners | Assays/evidence type | Quantitative stats | Primary source (date, URL) |
|---|---|---|---|---|---|---|
| Gene identity and core granule role | DEPS-1 is the product of deps-1 / Y65B4BL.2, a constitutive P-granule-associated protein required for proper PGL-1/PGL-3 localization and thus P-granule assembly | Cytoplasmic in germ cells and concentrated on P granules in adult germ line and late embryos; antibody P-granule staining lost in deps-1 mutants | Genetic/functional relationship upstream of PGL-1/PGL-3; also influences GLH-1 accumulation | Positional cloning/rescue, RNAi phenocopy, anti-DEPS-1 immunostaining, DEPS-1::GFP imaging, western blot | DEPS-1 protein ~69 kDa; orthologs show 45–51% identity in related Caenorhabditis spp.; 4 mutant alleles predicted strong LOF/null | Spike et al., “DEPS-1 promotes P-granule assembly and RNA interference in C. elegans germ cells” (Mar 2008), Development. https://doi.org/10.1242/dev.015552 |
| Fertility and germ-cell proliferation phenotype | DEPS-1 is required for fertility, gametogenesis, and normal germ-cell proliferation | Germ line / gonad arms | Linked functionally to constitutive P-granule machinery | Mutant phenotype scoring, germ-cell counting, temperature-shift analysis | In deps-1(bn121) M−Z− at 24.5°C, 93% sterile; 56% of germline arms had <200 germ nuclei; 63% lacked both sperm and oocytes; mean germ cells/gonad arm 254 ± 236 (n=16, range 10–762) vs wild type 586 ± 45 (n=6, range 526–651) | Spike et al., 2008 (Mar 2008), Development. https://doi.org/10.1242/dev.015552 |
| Germline RNAi support via RDE-4 | DEPS-1 promotes germline RNA interference, likely in part by supporting rde-4 mRNA/protein accumulation; RNAi defects are selective for germline/maternal targets | Germline P granules; post-transcriptional role inferred from cytoplasmic granule localization | Functional link to RDE-4; overlap with RDE-3/MUT-2-repressed gene sets | qRT-PCR, western blot, feeding RNAi assays, microarray comparison | rde-4 mRNA reduced 7–10-fold and RDE-4 protein ~10-fold lower in deps-1 M−Z− adults; strong resistance to pos-1/skn-1/pie-1 RNAi; overlap of upregulated genes with rde-3 dataset: 9/32 (~30%), P < 2.2 × 10⁻⁹; selected genes upregulated ~4- to 326-fold | Spike et al., 2008 (Mar 2008), Development. https://doi.org/10.1242/dev.015552 |
| Direct PRG-1 binding and piRNA-silencing role | DEPS-1 directly couples P granules to the piRNA pathway; required for piRNA-dependent silencing but not primary piRNA biogenesis | Perinuclear granules across adult germline regions; DEPS-1 and PRG-1 form intertwined elongated condensates | Direct interaction with PRG-1/PIWI via N-terminal PBS (PIWI-binding site) motif | PRG-1 IP-MS, colocalization imaging, MST biophysics, CRISPR PBS deletion, piRNA sensor assay | PRG-1 IP-MS recovered 133 proteins, DEPS-1 among top 10 interactors; MST Kdapp = 855 ± 133 nM (full-length PRG-1–DEPS-1), 349 ± 45 nM (PRG-1 PIWI–full-length DEPS-1), 1.9 µM ± 98 nM (PBS peptide–PRG-1 PIWI); deps-1 null and ΔPBS mutants desilence piRNA sensor | Suen et al., “DEPS-1 is required for piRNA-dependent silencing and PIWI condensate organisation in Caenorhabditis elegans” (Aug 2020), Nature Communications. https://doi.org/10.1038/s41467-020-18089-1 |
| Condensate ultrastructure and mutator-foci coupling | DEPS-1 organizes PRG-1 condensate morphology and helps maintain spatial coupling between P granules and mutator foci for downstream silencing | Perinuclear P granules; loss of PBS causes DEPS-1 cytoplasmic diffusion and compacted PRG-1 condensates | PRG-1, MUT-16, additional interactor EDG-1 | Live imaging, high-resolution microscopy, condensate morphometry, Y2H for EDG-1 | ΔPBS protein expressed at ~70% of WT; PRG-1 condensates become more compacted in deps-1 null/ΔPBS; PRG-1 morphometry sampled 20 condensates from 2 germlines (n=40 per genotype); deps-1 mutants show fewer, brighter MUT-16 foci; edg-1 knockdown specifically alters DEPS-1 condensates | Suen et al., 2020 (Aug 2020), Nature Communications. https://doi.org/10.1038/s41467-020-18089-1 |
| Secondary endo-siRNA / 22G homeostasis | DEPS-1 acts downstream of PRG-1 to promote secondary 22G endo-siRNAs from piRNA targets and affects multiple germline small-RNA pathways | Functional bridge between P granules and mutator foci | PRG-1-associated piRNA pathway; effects on WAGO, limited on ERGO-1, modest/complex on CSR-1 classes | Small-RNA sequencing, enrichment/overlap analyses, reporter silencing | 21U/piRNA levels remain similar to WT in deps-1 mutants, whereas prg-1 loses 21Us (one-sided t-test P < 10⁻²⁰, n=2); 300/425 WAGO targets show >2-fold 22G reduction (P < 10⁻¹³⁹); 7/23 ERGO-1 targets affected (P < 0.2); overlap with reduced CSR-1-target 22Gs 4/162 genes vs 447/2012 genes with >2-fold reduction (P < 10⁻¹³); sequencing often n=3 biological replicates | Suen et al., 2020 (Aug 2020), Nature Communications. https://doi.org/10.1038/s41467-020-18089-1 |
| Small RNAs target granule genes and explain transcript effects | DEPS-1 perturbation changes endo-siRNAs targeting granule factors and correlates with mRNA changes | Germline perinuclear granule system | Endo-siRNA targeting of P-granule factors broadly | Integrative analysis of small RNA and prior expression data | 8986/11,088 germline-expressed genes are endo-siRNA targets; 55/63 curated P-granule factors are endo-siRNA targets; 10/63 P-granule factors show differential 22Gs in deps-1 mutant; decrease in small RNAs correlates with mRNA increase (R² = 0.58, P < 0.01) | Suen et al., 2020 (Aug 2020), Nature Communications. https://doi.org/10.1038/s41467-020-18089-1 |
| Recent nanoscale localization update | 2023 expansion microscopy refines DEPS-1 placement within protein-dense P granules and shows P granule malformation in deps-1 mutants | DEPS-1 appears as small clusters localized within P granules; deps-1 mutants show reduced and sometimes nuclear-membrane-dissociated perinuclear granules | Spatial comparison with PRG-1, MUT-16, ZNFX-1 subdomains | Expansion microscopy (EExM), pan-protein staining, anti-DEPS-1/PRG-1 imaging, granule-size normalization | Average granules per nucleus: 2.5 ± 0.8 by GFP-DEPS-1 and 2.8 ± 1.3 by pan-stain (9 nuclei, 3 experiments); average expansion factor ~3× from 31 expanded nuclei / 6 experiments vs 47 non-expanded nuclei / 3 experiments; P granules smaller in deps-1(bn124) and mut-16(pk710), with significance P < 0.001 and P < 0.0001 depending on comparison | Suen et al., “Expansion microscopy reveals subdomains in C. elegans germ granules” (May 2023 preprint), bioRxiv. https://doi.org/10.1101/2022.05.29.493872 |
Table: This table summarizes core experimental findings for C. elegans DEPS-1, including function, localization, molecular partners, assay types, and quantitative results from the main primary studies. It is designed as a compact evidence map for functional annotation of UniProt Q9N303.
References
(spike2008deps1promotespgranule pages 4-5): Caroline A. Spike, Jason Bader, Valerie Reinke, and Susan Strome. Deps-1 promotes p-granule assembly and rna interference in c. elegans germ cells. Development, 135:983-993, Mar 2008. URL: https://doi.org/10.1242/dev.015552, doi:10.1242/dev.015552. This article has 98 citations and is from a domain leading peer-reviewed journal.
(suen2020deps1isrequired pages 8-9): Kin Man Suen, Fabian Braukmann, Richard Butler, Dalila Bensaddek, Alper Akay, Chi-Chuan Lin, Dovilė Milonaitytė, Neel Doshi, Alexandra Sapetschnig, Angus Lamond, John Edward Ladbury, and Eric Alexander Miska. Deps-1 is required for pirna-dependent silencing and piwi condensate organisation in caenorhabditis elegans. Text, Aug 2020. URL: https://doi.org/10.17863/cam.74696, doi:10.17863/cam.74696. This article has 28 citations and is from a peer-reviewed journal.
(spike2008deps1promotespgranule pages 7-8): Caroline A. Spike, Jason Bader, Valerie Reinke, and Susan Strome. Deps-1 promotes p-granule assembly and rna interference in c. elegans germ cells. Development, 135:983-993, Mar 2008. URL: https://doi.org/10.1242/dev.015552, doi:10.1242/dev.015552. This article has 98 citations and is from a domain leading peer-reviewed journal.
(suen2020deps1isrequired pages 3-4): Kin Man Suen, Fabian Braukmann, Richard Butler, Dalila Bensaddek, Alper Akay, Chi-Chuan Lin, Dovilė Milonaitytė, Neel Doshi, Alexandra Sapetschnig, Angus Lamond, John Edward Ladbury, and Eric Alexander Miska. Deps-1 is required for pirna-dependent silencing and piwi condensate organisation in caenorhabditis elegans. Text, Aug 2020. URL: https://doi.org/10.17863/cam.74696, doi:10.17863/cam.74696. This article has 28 citations and is from a peer-reviewed journal.
(suen2020deps1isrequired media a9234a31): Kin Man Suen, Fabian Braukmann, Richard Butler, Dalila Bensaddek, Alper Akay, Chi-Chuan Lin, Dovilė Milonaitytė, Neel Doshi, Alexandra Sapetschnig, Angus Lamond, John Edward Ladbury, and Eric Alexander Miska. Deps-1 is required for pirna-dependent silencing and piwi condensate organisation in caenorhabditis elegans. Text, Aug 2020. URL: https://doi.org/10.17863/cam.74696, doi:10.17863/cam.74696. This article has 28 citations and is from a peer-reviewed journal.
(suen2020deps1isrequired pages 4-5): Kin Man Suen, Fabian Braukmann, Richard Butler, Dalila Bensaddek, Alper Akay, Chi-Chuan Lin, Dovilė Milonaitytė, Neel Doshi, Alexandra Sapetschnig, Angus Lamond, John Edward Ladbury, and Eric Alexander Miska. Deps-1 is required for pirna-dependent silencing and piwi condensate organisation in caenorhabditis elegans. Text, Aug 2020. URL: https://doi.org/10.17863/cam.74696, doi:10.17863/cam.74696. This article has 28 citations and is from a peer-reviewed journal.
(suen2020deps1isrequired pages 9-10): Kin Man Suen, Fabian Braukmann, Richard Butler, Dalila Bensaddek, Alper Akay, Chi-Chuan Lin, Dovilė Milonaitytė, Neel Doshi, Alexandra Sapetschnig, Angus Lamond, John Edward Ladbury, and Eric Alexander Miska. Deps-1 is required for pirna-dependent silencing and piwi condensate organisation in caenorhabditis elegans. Text, Aug 2020. URL: https://doi.org/10.17863/cam.74696, doi:10.17863/cam.74696. This article has 28 citations and is from a peer-reviewed journal.
(suen2023expansionmicroscopyreveals pages 11-15): Kin M. Suen, Thomas M. D. Sheard, Chi-Chuan Lin, Dovile Milonaityte, Izzy Jayasinghe, and John E. Ladbury. Expansion microscopy reveals subdomains in c. elegans germ granules. bioRxiv, May 2023. URL: https://doi.org/10.1101/2022.05.29.493872, doi:10.1101/2022.05.29.493872. This article has 6 citations.