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this with annotations you find in gene/protein databases, but these can be outdated or inaccurate.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 gene symbol Dmel\CG3515 is not itself ambiguous in the supplied UniProt context, but literature is extremely limited for this specific protein. The target is Drosophila melanogaster CG3515 (FlyBase FBgn0031431; UniProt Q9VQD1), annotated as a WD-repeat protein belonging to the SWD2 family. Comparative sequence work explicitly included Dm_CG3515 among SWD2-related proteins and supports WD40-repeat architecture, probably a seven-bladed β-propeller (dichtl2004functionsfors. pages 2-3, dichtl2004functionsfors. pages 3-3).
However, the experimentally studied fly protein commonly called Wdr82/dWdr82 appears to be the separate locus CG17293, not CG3515. CG3515 and CG17293 are listed separately in comparative SWD2-family analysis, and CG17293 has independently been described as highly related to mammalian WDR82 (dichtl2004functionsfors. pages 3-3, park2011molecularorganizationof pages 4-5). Therefore, results on dWdr82-dependent COMPASS activity, H3K4 trimethylation, and Su(s)-mediated transcription termination must not be assigned to Q9VQD1/CG3515.
The defensible functional annotation is consequently narrow: CG3515 is most likely a nonenzymatic WD40 interaction scaffold, but its binding partners, complex membership, pathway, cellular localization, and organismal role have not been established experimentally.
| Claim/topic | Finding | Evidence type | Confidence | Key caveat |
|---|---|---|---|---|
| Target identity | Q9VQD1 corresponds to Drosophila melanogaster CG3515 (FBgn0031431), annotated as a WD repeat-containing protein in the SWD2 family. Comparative literature explicitly includes Dm_CG3515 among SWD2-related sequences (dichtl2004functionsfors. pages 2-3, dichtl2004functionsfors. pages 3-3) | Curated database annotation plus comparative sequence evidence | High | The protein name is annotation-based; it does not demonstrate a particular biochemical role in flies. |
| Predicted structure | Sequence/profile analysis supports WD40-repeat architecture, plausibly forming a seven-bladed β-propeller typical of SWD2-family scaffolds (dichtl2004functionsfors. pages 2-3, dichtl2004functionsfors. pages 3-3) | Bioinformatic and evolutionary inference | Moderate–high | No experimentally determined CG3515 structure was identified; the seven-bladed model is predicted rather than directly measured. |
| Primary molecular function | CG3515 is most plausibly a nonenzymatic protein-interaction scaffold or adaptor, not an enzyme, transporter, receptor, or structural filament protein. | Domain/family inference | Moderate | No CG3515-specific catalytic assay, binding assay, interaction map, or substrate-specificity study was found. |
| Complex membership and pathway | No direct evidence identified that CG3515 belongs to Drosophila COMPASS, a cleavage/polyadenylation complex, or a transcription-termination complex. Yeast SWD2 has dual SET1C and CPF roles, but these cannot be automatically transferred to CG3515 (dichtl2004functionsfors. pages 2-3) | Cross-species family analogy | Low for CG3515 | Orthology within a diversified WD-repeat family is insufficient to establish conserved complex membership. |
| Cellular localization | No experimentally validated cellular or subcellular localization was found for CG3515. | Negative literature finding | Undetermined | A nuclear localization would be plausible only if a transcription/chromatin role were independently confirmed. |
| Genetic or organismal function | No CG3515-specific loss-of-function phenotype, rescue experiment, tissue-specific perturbation, or validated biological process was identified. | Negative literature finding | Undetermined | High-throughput screens or database predictions should not be interpreted as mechanistic validation. |
| Distinction from fly Wdr82 | CG17293 is a separate Drosophila locus described as highly related to mammalian WDR82; functional fly studies of “dWdr82” connect that protein to COMPASS-dependent H3K4 trimethylation and Su(s)-associated transcription termination (mohan2011thecompassfamily pages 5-7, brewerjensen2016suppressorofsable pages 11-12, park2011molecularorganizationof pages 4-5) | Locus-specific literature disambiguation | High | These CG17293/dWdr82 findings must not be attributed to CG3515/Q9VQD1. |
| Peroxisomal DBP false match | A peroxisome review’s apparent “CG3515” reference concerns a D-bifunctional-protein homolog and is inconsistent with the surrounding identification of CG3415; it is unrelated to Q9VQD1 and is best treated as a typographical or identifier error (faust2012aninventoryof pages 3-5) | Contextual identifier audit | High | It provides no evidence that Q9VQD1 is peroxisomal or participates in fatty-acid β-oxidation. |
| Recent 2023–2024 context | Mammalian studies place WDR82 in ZC3H4 Restrictor-mediated early termination and in SET1-associated protection from premature termination; related work links WDR82 to PNUTS/PP1 and Pol II regulation (polizzese2024terminationofextragenic pages 26-30, mandana2025investigatingthebases pages 24-25, polizzese2024terminationofextragenic pages 22-26) | Recent mammalian mechanistic evidence | High for mammalian WDR82; low for fly CG3515 | No 2023–2024 study directly validating these mechanisms for CG3515 was identified. |
Table: Evidence-tier summary separating experimentally supported identity and domain features of CG3515/Q9VQD1 from unvalidated functional inference. It highlights the critical distinction between CG3515 and the separate Drosophila Wdr82-associated locus CG17293.
The 2004 SWD2 comparative analysis explicitly includes “Dm_CG3515” and separately lists Dm_CG17293. Thus, the two identifiers refer to distinct fly proteins rather than aliases of one locus (dichtl2004functionsfors. pages 3-3). The paper is primarily a yeast study and supplies comparative-sequence—not direct fly-functional—evidence [Dichtl et al., June 2004; DOI URL: https://doi.org/10.1261/rna.7090104] (dichtl2004functionsfors. pages 2-3).
CG3515 contains WD40-repeat/domain signatures. WD40 proteins generally fold into β-propeller platforms whose exposed surfaces organize protein–protein interactions. Comparative profile analysis of SWD2-family sequences predicts up to seven WD repeats and a seven-bladed β-propeller; this is consistent with the supplied InterPro/Pfam assignments but has not been validated by a CG3515 crystal structure or cryo-EM model (dichtl2004functionsfors. pages 2-3, dichtl2004functionsfors. pages 3-3).
Accordingly, CG3515 is best classified as a putative protein-interaction scaffold or adaptor. There is no evidence that it catalyzes a chemical reaction, binds a transport substrate, forms a structural filament, or possesses intrinsic methyltransferase or phosphatase activity. Questions of catalytic reaction and substrate specificity are therefore not applicable on current evidence.
The protein description “WD repeat-containing protein 82” should be treated cautiously: it reflects homology/domain annotation, not proof that CG3515 performs all functions of mammalian WDR82. In particular, assigning it as a Pol II CTD receptor, SET1-complex subunit, or transcription-termination factor would exceed the target-specific evidence.
Only the following is presently well supported:
No retrieved study directly demonstrated CG3515 participation in:
Yeast Swd2 is a shared component of two functionally distinct assemblies: SET1C, which supports histone H3 lysine-4 methylation, and cleavage/polyadenylation factor, which participates in mRNA and snoRNA 3′-end formation. Temperature-sensitive yeast mutants displayed defects in specific RNA 3′-end processing, reduced H3K4 di- and trimethylation, lower Set1 abundance, and shortened telomeres [Dichtl et al., June 2004; https://doi.org/10.1261/rna.7090104] (dichtl2004functionsfors. pages 2-3).
These findings provide a biologically plausible hypothesis for CG3515, but not a verified annotation. The separate existence of CG17293 indicates that SWD2-family functions may have diverged or partitioned between fly paralogs. Orthology resolution and complex proteomics are required before the yeast dual-function model can be transferred to CG3515.
In Drosophila S2 cells, depletion of dWdr82 significantly reduced H3K4 trimethylation while leaving H3K4 dimethylation comparatively unaffected, consistent with a role in trimethylation-competent COMPASS [Mohan et al., November 2011; https://doi.org/10.1128/MCB.06092-11] (mohan2011thecompassfamily pages 5-7). Separately, dWdr82 and Su(s) inhibit Pol II elongation through heat-shock-inducible Hsp70-αβ repetitive elements and promote production of unstable, heterogeneously polyadenylated transcripts. Su(s) becomes less stable without Wdr82, and the pathway likely acts upstream of nuclear-exosome degradation [Brewer-Jensen et al., January 2016 issue; DOI metadata retrieved November 2016; https://doi.org/10.1261/rna.048819.114] (brewerjensen2016suppressorofsable pages 11-12).
These are important demonstrations of SWD2/WDR82-family biology in flies, but because the functional papers do not establish CG3515 as their tested locus—and independent evidence points to CG17293—they should be used only as hypotheses for Q9VQD1.
No experimentally validated localization was found for CG3515/Q9VQD1. A nuclear or chromatin-associated location would be plausible if CG3515 participates in transcription or chromatin regulation, but this remains an inference.
The Su(s)-dWdr82 pathway operates in a nuclear transcriptional context: Su(s) associates with polytene-chromosome sites containing hypophosphorylated or Ser5-phosphorylated Pol II, and S2-cell experiments measured Pol II occupancy after RNAi and heat shock (brewerjensen2016suppressorofsable pages 11-12, brewerjensen2016suppressorofsable pages 14-15). This does not constitute localization evidence for CG3515 itself.
There is likewise no valid evidence for peroxisomal localization. The apparent peroxisomal “CG3515” mention is embedded in a discussion of CG3415 and is inconsistent with the target’s WD-repeat identity (faust2012aninventoryof pages 3-5).
No 2023–2024 publication directly characterizing CG3515 was identified. Recent advances concern mammalian WDR82 and clarify why simple transfer to CG3515 is hazardous.
A 2023 mammalian study showed that SET1 complexes protect low-to-moderately transcribed CpG-island genes from premature termination. This protective effect can be independent of SET1 histone-methyltransferase activity and depends on interaction with WDR82; at extragenic transcription sites, ZC3H4/WDR82 Restrictor activity remains unopposed [Hughes et al., March 2023; https://doi.org/10.1038/s41467-023-36236-2]. In current models, mammalian WDR82 is a WD40 adaptor used in several nuclear assemblies: SET1A/B–COMPASS at promoters, ZC3H4–WDR82 Restrictor during early noncoding transcription, and PNUTS–PP1-associated termination machinery near gene ends (polizzese2024terminationofextragenic pages 26-30, polizzese2024terminationofextragenic pages 22-26, kelley2022characterisingthemolecular pages 32-35).
A December 2023 study further reported that the core WDR82–ZC3H4 Restrictor machinery cooperates with Symplekin and PNUTS to terminate extragenic transcription [Russo et al., December 2023; https://doi.org/10.1101/gad.351057.123]. A July 2024 preprint proposed direct interaction between PNUTS and Restrictor through a WDR82-binding domain and linked PP1-dependent Pol II CTD Ser5 dephosphorylation to termination [Erickson et al., July 2024; https://doi.org/10.1101/2024.07.12.603302]. These developments sharpen the family-level hypothesis that WDR82 proteins bridge Pol II to regulatory complexes, but they do not identify CG3515 as the fly executor of those functions.
There is no established clinical, agricultural, diagnostic, or biotechnology application specific to CG3515. Its most immediate value is as an annotation and functional-genomics target:
Mammalian WDR82 pathways are relevant to transcriptional control, retroelement restriction, and HIV latency, but these applications concern mammalian WDR82 complexes, not CG3515. For example, a 2023 study identified PCF11–WDR82 as a premature-termination complex that attenuates latent HIV-1 transcription [Ait Said et al., November 2023; https://doi.org/10.1073/pnas.2313356120].
Target-specific quantitative data are essentially absent. The strongest numerical feature associated with CG3515 is the predicted seven-repeat/seven-bladed WD40 architecture, which remains computational rather than structural evidence (dichtl2004functionsfors. pages 3-3).
Quantitative results found in nearby literature belong to other genes. For example, the CRL4Mahj study reported large changes in EdU- and PH3-positive neural stem cells after perturbing CG10080/Mahjong, while CG3515 was only a screened candidate; these values must not be attributed to CG3515 (ly2019crl4mahje3ubiquitin pages 7-9). Likewise, significant loss of H3K4me3 after dWdr82 RNAi supports the function of the separately studied fly Wdr82 protein, not Q9VQD1 (mohan2011thecompassfamily pages 5-7).
CG3515/Q9VQD1 is a poorly characterized Drosophila melanogaster SWD2-family WD40-repeat protein, most likely functioning as a protein-interaction scaffold. No direct evidence currently establishes its complex membership, pathway, localization, substrate, or biological phenotype. Functional Drosophila studies of Wdr82 most likely concern the distinct CG17293 locus and must not be transferred to CG3515. The leading—but unvalidated—hypothesis is that CG3515 participates in a nuclear multiprotein assembly involved in chromatin or RNA metabolism, based solely on its conserved SWD2/WD40 architecture and cross-species family biology.
References
(dichtl2004functionsfors. pages 2-3): BERNHARD DICHTL, REIN AASLAND, and WALTER KELLER. Functions for s. cerevisiae swd2p in 3' end formation of specific mrnas and snornas and global histone 3 lysine 4 methylation. RNA, 10 6:965-77, Jun 2004. URL: https://doi.org/10.1261/rna.7090104, doi:10.1261/rna.7090104. This article has 89 citations and is from a domain leading peer-reviewed journal.
(dichtl2004functionsfors. pages 3-3): BERNHARD DICHTL, REIN AASLAND, and WALTER KELLER. Functions for s. cerevisiae swd2p in 3' end formation of specific mrnas and snornas and global histone 3 lysine 4 methylation. RNA, 10 6:965-77, Jun 2004. URL: https://doi.org/10.1261/rna.7090104, doi:10.1261/rna.7090104. This article has 89 citations and is from a domain leading peer-reviewed journal.
(park2011molecularorganizationof pages 4-5): Dongkook Park, Tarik Hadžić, Ping Yin, Jannette Rusch, Katharine Abruzzi, Michael Rosbash, James B. Skeath, Satchidananda Panda, Jonathan V. Sweedler, and Paul H. Taghert. Molecular organization of drosophila neuroendocrine cells by dimmed. Current Biology, 21:1515-1524, Sep 2011. URL: https://doi.org/10.1016/j.cub.2011.08.015, doi:10.1016/j.cub.2011.08.015. This article has 44 citations and is from a highest quality peer-reviewed journal.
(mohan2011thecompassfamily pages 5-7): Man Mohan, Hans-Martin Herz, Edwin R. Smith, Ying Zhang, Jessica Jackson, Michael P. Washburn, Laurence Florens, Joel C. Eissenberg, and Ali Shilatifard. The compass family of h3k4 methylases in drosophila. Nov 2011. URL: https://doi.org/10.1128/mcb.06092-11, doi:10.1128/mcb.06092-11. This article has 273 citations and is from a domain leading peer-reviewed journal.
(brewerjensen2016suppressorofsable pages 11-12): Paul Brewer-Jensen, Carrie B. Wilson, John Abernethy, Lonna Mollison, Samantha Card, and Lillie L. Searles. Suppressor of sable [su(s)] and wdr82 down-regulate rna from heat-shock-inducible repetitive elements by a mechanism that involves transcription termination. RNA, 22(1):139-154, Nov 2016. URL: https://doi.org/10.1261/rna.048819.114, doi:10.1261/rna.048819.114. This article has 34 citations and is from a domain leading peer-reviewed journal.
(faust2012aninventoryof pages 3-5): Joseph E. Faust, Avani Verma, Chengwei Peng, and James A. McNew. An inventory of peroxisomal proteins and pathways in drosophila melanogaster. Traffic, 13:1378-1392, Oct 2012. URL: https://doi.org/10.1111/j.1600-0854.2012.01393.x, doi:10.1111/j.1600-0854.2012.01393.x. This article has 112 citations and is from a peer-reviewed journal.
(polizzese2024terminationofextragenic pages 26-30): D Polizzese. Termination of extragenic transcription by the restrictor complex: dissecting rna binding specificity. Unknown journal, 2024.
(mandana2025investigatingthebases pages 24-25): GM Mandana. Investigating the bases of the specificity of the restrictor complex for the termination of noncoding transcription. Unknown journal, 2025.
(polizzese2024terminationofextragenic pages 22-26): D Polizzese. Termination of extragenic transcription by the restrictor complex: dissecting rna binding specificity. Unknown journal, 2024.
(ly2019crl4mahje3ubiquitin pages 7-9): Phuong Thao Ly, Ye Sing Tan, Chwee Tat Koe, Yingjie Zhang, Gengqiang Xie, Sharyn Endow, Wu-Min Deng, Fengwei Yu, and Hongyan Wang. Crl4mahj e3 ubiquitin ligase promotes neural stem cell reactivation. Jun 2019. URL: https://doi.org/10.1371/journal.pbio.3000276, doi:10.1371/journal.pbio.3000276. This article has 32 citations and is from a highest quality peer-reviewed journal.
(brewerjensen2016suppressorofsable pages 14-15): Paul Brewer-Jensen, Carrie B. Wilson, John Abernethy, Lonna Mollison, Samantha Card, and Lillie L. Searles. Suppressor of sable [su(s)] and wdr82 down-regulate rna from heat-shock-inducible repetitive elements by a mechanism that involves transcription termination. RNA, 22(1):139-154, Nov 2016. URL: https://doi.org/10.1261/rna.048819.114, doi:10.1261/rna.048819.114. This article has 34 citations and is from a domain leading peer-reviewed journal.
(kelley2022characterisingthemolecular pages 32-35): Characterising the molecular basis of WDR82 binding in multiple contexts This article has 0 citations.