| Aspect | Key findings | Key sources | URL/DOI |
|---|---|---|---|
| identity/domains | **Identity verified:** *Caenorhabditis elegans* **znfx-1** encodes ZNFX-1, a deeply conserved **ZNFX1-family / NFX1-type zinc finger-containing** protein localized to germline nuage. Domain architecture includes a **central UPF1-like SF1 helicase domain** and **six cysteine-rich NF-X1-like motifs**; the helicase and cysteine-rich regions are both required for epigenetic inheritance. This matches UniProt E9P860 family/domain annotations (helicase/P-loop NTPase/Upf1-like). (pqac-00000004, pqac-00000006) | Ishidate 2018 | https://doi.org/10.1016/j.molcel.2018.04.009 |
| molecular activity | ZNFX-1 is experimentally supported as an **RNA helicase/NTPase-like factor** acting in small-RNA amplification rather than a classical metabolic enzyme with a defined soluble substrate. Genetic evidence from the **ATP-binding-site mutant K1067A** and helicase-domain deletions shows the helicase core is functionally essential. Mechanistically, authors propose Argonautes recruit ZNFX-1 to target mRNAs, after which ZNFX-1 helps position RdRP to favor **3' recruitment** and balanced 22G-RNA synthesis along transcripts; in 2022 work, ZNFX-1 binds **pUGylated target RNAs** and sustains their use as templates for tertiary sRNA amplification. (pqac-00000004, pqac-00000005, pqac-00000001) | Ishidate 2018; Ouyang 2022 | https://doi.org/10.1016/j.molcel.2018.04.009; https://doi.org/10.1038/s41556-022-00940-w |
| binding partners | Co-immunoprecipitation shows ZNFX-1 interacts with **RdRP EGO-1** and Argonautes **CSR-1, WAGO-1, PRG-1**; the **ZNFX-1:EGO-1** and **ZNFX-1:CSR-1** interactions are **RNase I resistant**, while interactions with WAGO-1/PRG-1 are partly RNA-sensitive. Earlier inheritance studies also support biochemical/functional partnership with **WAGO-4**. (pqac-00000000, pqac-00000007) | Ishidate 2018; Wan 2017/2018 | https://doi.org/10.1016/j.molcel.2018.04.009; https://doi.org/10.1038/s41586-018-0132-0 |
| localization | ZNFX-1 localizes to **perinuclear nuage/germ granules** in the germline. It initially overlaps **P granules** in early germline blastomeres, then demixes with WAGO-4 to form **Z granules**, later assembling into ordered **PZM tri-condensates** with P granules and Mutator foci. Imaging metrics: in adult germ cells, **60% (52/86)** of Z granules were apposed to both a P granule and Mutator focus, and in **92% (48/52)** of those, the Z granule lay between them. In wild type, GFP::ZNFX-1 granules are adjacent to but separate from PGL-1 foci; in **eggd-1** mutants, perinuclear ZNFX-1 is reduced and redistributes to the rachis. (pqac-00000002, pqac-00000003, pqac-00000014, pqac-00000015) | Wan 2018; Ishidate 2018; Price 2023 | https://doi.org/10.1038/s41586-018-0132-0; https://doi.org/10.1016/j.molcel.2018.04.009; https://doi.org/10.1038/s41467-023-41556-4 |
| pathway roles | ZNFX-1 is a core factor in **RNAi inheritance / transgenerational epigenetic inheritance (TEI)** and endogenous germline small-RNA regulation. It acts in a **cytoplasmic/perinuclear amplification loop** parallel to nuclear **HRDE-1**: HRDE-1 targets nascent transcripts, while ZNFX-1 targets **mature transcripts** in nuage, maintains **pUGylated RNAs**, and promotes robust tertiary 22G-RNA amplification in inheriting generations. It also helps balance outputs of **WAGO/PRG-1/CSR-1** systems rather than acting solely as a silencing factor. (pqac-00000001, pqac-00000005, pqac-00000006, pqac-00000010) | Ishidate 2018; Ouyang 2022 | https://doi.org/10.1016/j.molcel.2018.04.009; https://doi.org/10.1038/s41556-022-00940-w |
| phenotypes/quant data | **RNAe maintenance defects:** znfx-1 deletion or helicase/cysteine-rich mutants cause premature desilencing of silent transgenes; stable GFP expression appeared by **F5** for deletion/K1067A/L1530F and by **F6** for Y1562C, whereas at **15°C** expression did not stabilize for **>10 generations** until shift to **25°C**. Mutant protein abundance was reduced to about **10–25%** of WT for several alleles. **Small RNAs:** overall 22G-RNA abundance increased by about **12%** in one mutant analysis, especially among WAGO targets, but distribution became mispatterned toward 5' ends. In RNAi inheritance assays, wild-type F1 animals showed a **23-fold** increase in mex-6 sRNAs; **hrde-1** retained about **83%** of WT, while **znfx-1** retained only about **6%** and lacked enrichment at the trigger region. In P0 animals, mex-6 sRNAs rose about **200-fold** in both WT and znfx-1, with only a **~16%** reduction in znfx-1, showing a stronger requirement in inheriting generations. (pqac-00000000, pqac-00000003, pqac-00000004, pqac-00000010) | Ishidate 2018; Ouyang 2021/2022 | https://doi.org/10.1016/j.molcel.2018.04.009; https://doi.org/10.1101/2021.08.13.456232; https://doi.org/10.1038/s41556-022-00940-w |
| 2023-2024 developments/methods | **2023:** Cytoplasm-only inheritance assays showed RNAi can be inherited through ooplasm and that **znfx-1 mutants are defective in cytoplasmic inheritance**. In the GPR-1(OE) chimera system, cytoplasm-only inheritance yielded **85.56 ± 6.65%** viable F3 progeny in controls but only **24.49 ± 8.91%** in znfx-1 mutants; under one more stringent cytoplasm-only condition, residual inheritance in znfx-1 was **6.87 ± 3.54%**, while **pptr-1** granule-segregation mutants partially bypassed the need for znfx-1 (**19.25 ± 10.94%** viable progeny). Sequencing showed inherited ZNFX-1-class small RNAs were enriched **6.2-fold (P < 0.0001)**. **2023 imaging:** in eggd-1 mutants, mean GFP::ZNFX-1 granule volume changed by **2.32-fold decrease** at the nuclear periphery and **1.64-fold decrease** in the rachis relative to WT perinuclear granules. **2024:** broader condensate studies further placed ZNFX-1-positive Z granules within specialized germ-granule architecture coordinating small-RNA production and inheritance, including use of endogenous fluorescent tagging and proximity-labeling/TurboID-style approaches in the Z-granule field. (pqac-00000008, pqac-00000009, pqac-00000012, pqac-00000014, pqac-00000015) | Rieger 2023; Price 2023; Chen 2024; Zhao 2024 | https://doi.org/10.1126/sciadv.adj8618; https://doi.org/10.1038/s41467-023-41556-4; https://doi.org/10.1038/s41467-024-50027-3; https://doi.org/10.1038/s41556-024-01514-8 |


*Table: This table summarizes experimentally supported functional annotation for *C. elegans* znfx-1/ZNFX-1, including identity, molecular role, localization, pathway function, and recent 2023-2024 developments. It is useful as a compact evidence map linking key claims to primary literature and quantitative findings.*