Functional annotation report: *Neurospora crassa* NCU11362 / UniProt A7UX10 Falcon Edison Scientific Literature 13 citations 1 artifacts 2026-09-08T20:09:06.254247

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Functional annotation report: Neurospora crassa NCU11362 / UniProt A7UX10

Executive conclusion

The gene symbol NCU11362 is not ambiguous in the supplied context: it refers to UniProt A7UX10, an ORF from Neurospora crassa strain ATCC 24698 / 74-OR23-1A and its equivalent collection aliases. Its supplied annotations—DUF890, InterPro METTL16/RlmF (IPR010286), SAM-dependent methyltransferase superfamily (IPR029063), and Pfam Methyltransf_10 (PF05971)—are mutually consistent with a putative RNA methyltransferase.

However, the gene symbol and accession produced no gene-specific scientific publication in the searches performed. None of the retrieved literature reports an NCU11362 knockout phenotype, purified-enzyme assay, RNA substrate, expression profile, interaction, structure, subcellular localization, or pathway assignment. Accordingly, the required cautionary statement applies: “The gene symbol ‘NCU11362’ is ambiguous or literature is limited for this specific protein.” Here the issue is limited literature, rather than evidence for a conflicting gene. The strongest defensible annotation is therefore:

NCU11362/A7UX10 is a predicted SAM-dependent RNA methyltransferase-family protein, plausibly an RNA adenine-N6 methyltransferase, but its catalytic activity, physiological RNA substrate, modified nucleotide, localization, and biological pathway remain experimentally unknown.

Topic Best-supported conclusion Evidence type/grade Important limitation
Identity NCU11362 corresponds to UniProt A7UX10 from Neurospora crassa strain ATCC 24698 / 74-OR23-1A and its listed aliases. Annotation fact: UniProt identity supplied by the user. No gene-specific publication was identified independently confirming function.
Domain architecture Annotated with METTL16/RlmF (IPR010286), SAM-dependent methyltransferase superfamily (IPR029063), and Methyltransf_10/PF05971 domains; originally described as DUF890-containing. Database/domain annotation: Supplied by the user; supportive of family membership but not direct functional proof. Domain calls do not establish that NCU11362 is a one-to-one METTL16 ortholog, an active enzyme, or a protein with a particular substrate.
Catalytic class NCU11362 is predicted to be a Class-I SAM-dependent methyltransferase, possibly acting on RNA. METTL16 has a Rossmann-like fold, a SAM/SAH-binding GXG region, a catalytic NPPF motif, and a positively charged RNA-binding groove (ruszkowska2018structuralinsightsinto pages 5-7, ruszkowska2018structuralinsightsinto pages 3-5, ruszkowska2018structuralinsightsinto pages 2-3). Moderate homolog/domain inference. The motifs, fold, cofactor binding, and catalytic activity have not been experimentally demonstrated for NCU11362.
Proposed reaction Working hypothesis: SAM + RNA adenosine → SAH + RNA N6-methyladenosine (m6A). This reaction is established for human METTL16, not NCU11362 (ruszkowska2018structuralinsightsinto pages 5-7, ruszkowska2018structuralinsightsinto pages 1-2). Low-to-moderate homolog inference; unvalidated for the target. No NCU11362 enzyme assay, kinetic measurement, catalytic-site mutant, or product analysis is available.
Possible RNA substrates Plausible substrates include structured cellular RNAs. Human METTL16 methylates U6 snRNA and MAT2A RNA, whereas bacterial RlmF targets A1618 of 23S rRNA (ruszkowska2018structuralinsightsinto pages 9-10, ruszkowska2018structuralinsightsinto pages 11-11). Low-confidence family analogy. U6, mRNA, cytosolic rRNA, mitochondrial rRNA, and the exact target nucleotide are all unknown for NCU11362; substrate specificity cannot be transferred across distant family members.
Localization Unknown. Nuclear or nucleolar localization would be plausible if the substrate were U6 or pre-ribosomal RNA; mitochondrial localization would be plausible only if it modified organellar RNA. No target-specific evidence; hypothesis only. Human and Drosophila METTL16 localization does not establish the localization of fungal NCU11362 (spagnuolo2024uncoveringthefunctions pages 4-6, ruszkowska2018structuralinsightsinto pages 9-10).
Biological pathway The most plausible broad assignment is RNA modification or RNA maturation, potentially involving splicing or ribosome biogenesis depending on the true substrate. Low-confidence functional inference. No Neurospora pathway assignment, genetic interaction, RNA-modification map, or substrate-dependent phenotype connects NCU11362 to either pathway.
Gene-specific experiments No retrieved study reported an NCU11362/A7UX10 biochemical assay, mutant phenotype, expression profile, interaction, localization, structure, pathway test, or direct orthology analysis (spagnuolo2024uncoveringthefunctions pages 4-6, ruszkowska2018structuralinsightsinto pages 9-10). Unknown / evidence gap. Absence from the retrieved literature does not prove that unpublished or unindexed data do not exist.
Recent 2023–2024 developments A 2024 Drosophila thesis reports that a Drosophila METTL16 ortholog is predominantly nuclear, binds U6 RNA, and contributes to ovarian development; these are not findings about NCU11362 (spagnuolo2024uncoveringthefunctions pages 4-6, spagnuolo2024uncoveringthefunctions pages 27-30). Recent, indirect comparative evidence only. No 2023–2024 publication specific to NCU11362/A7UX10 was found, and metazoan findings must not be assigned to this fungal protein.

Table: Evidence-graded conclusions for NCU11362/A7UX10 distinguish supplied database annotations from METTL16/RlmF-family inference and unresolved target-specific questions.

1. Identity verification

Target matched

No retrieved paper mentioned NCU11362 or A7UX10 in another organism, and no conflicting same-symbol protein was substituted. Importantly, a domain label of “METTL16/RlmF” does not by itself establish that A7UX10 is the fungal ortholog of human METTL16, nor that it has the substrate specificity of bacterial RlmF.

2. Primary molecular function

Most likely catalytic class

The domain combination supports classification as a Class-I S-adenosyl-L-methionine-dependent methyltransferase, probably acting on RNA. Experimentally characterized human METTL16 has a Rossmann-like methyltransferase fold, a SAM/SAH-binding region containing a GXG feature, a conserved NPPF catalytic-region motif, and a positively charged groove consistent with RNA binding. Mutating residues within the human NPPF region abolishes or strongly impairs methylation activity (ruszkowska2018structuralinsightsinto pages 5-7, ruszkowska2018structuralinsightsinto pages 3-5, ruszkowska2018structuralinsightsinto pages 2-3).

These observations support a family-level hypothesis for A7UX10, but the relevant motifs and their integrity should be verified directly in its sequence before assigning catalytic activity.

Proposed reaction

If A7UX10 retains METTL16/RlmF-like chemistry, the predicted reaction is:

S-adenosyl-L-methionine + adenosine in RNA → S-adenosyl-L-homocysteine + N6-methyladenosine in RNA.

Human METTL16 transfers the SAM methyl group to the exocyclic N6 amino group of RNA adenosine through a proposed SN2-like methyl-transfer mechanism. The resulting modification is m6A (ruszkowska2018structuralinsightsinto pages 5-7, ruszkowska2018structuralinsightsinto pages 1-2).

Evidence grade for NCU11362: low-to-moderate computational inference. There is no A7UX10 assay showing SAM binding, SAH production, methyl transfer, or m6A formation.

3. Substrate specificity

The physiological substrate of NCU11362 is unknown. Two distinct family analogies define the main alternatives:

  1. METTL16-like activity. Human METTL16 methylates U6 spliceosomal RNA and MAT2A RNA. METTL16 substrates are not simply restricted to the canonical METTL3/METTL14 RRACH sequence; RNA structure and presentation of an extrahelical adenosine appear important (ruszkowska2018structuralinsightsinto pages 3-5, ruszkowska2018structuralinsightsinto pages 9-10).
  2. RlmF-like activity. Bacterial RlmF/YbiN modifies A1618 of 23S rRNA, providing a competing ribosomal-RNA interpretation of the same broad family annotation (ruszkowska2018structuralinsightsinto pages 9-10, ruszkowska2018structuralinsightsinto pages 11-11).

Thus, it would be premature to annotate A7UX10 specifically as a U6 methyltransferase, MAT2A regulator, or 23S/large-subunit rRNA A1618 methyltransferase. Eukaryotic cytosolic and mitochondrial ribosomes also differ from bacterial ribosomes in RNA numbering and enzyme targeting, so the bacterial residue number cannot be transferred directly.

4. Cellular localization

No target-specific localization evidence was found. The appropriate annotation is localization unknown.

Possible locations depend on substrate:

Human METTL16 is nuclear and interacts with several RNA classes, but that observation cannot establish A7UX10 localization (ruszkowska2018structuralinsightsinto pages 9-10). Likewise, 2024 Drosophila work describing a predominantly nuclear METTL16 ortholog does not constitute evidence for this fungal protein (spagnuolo2024uncoveringthefunctions pages 4-6).

5. Biological process and pathway

The broadest defensible process assignment is RNA modification/RNA maturation. More precise alternatives are:

No N. crassa genetic or biochemical evidence currently connects NCU11362 to any of these pathways. In particular, mammalian METTL16’s regulation of MAT2A and SAM homeostasis should not be assigned to the fungal protein without identification of a corresponding RNA target.

6. Recent research, 2023–2024

No 2023–2024 paper specific to NCU11362/A7UX10 was identified. The most relevant recent comparative result is a 2024 Drosophila doctoral study reporting that the fly METTL16 ortholog CG7544 is predominantly nuclear, binds U6 RNA, is enriched in ovaries, and contributes to ovarian development and fertility. These findings reinforce the biological importance of METTL16-family RNA modification in metazoans, but they do not establish orthology, localization, substrate, or phenotype for A7UX10 (spagnuolo2024uncoveringthefunctions pages 4-6, spagnuolo2024uncoveringthefunctions pages 27-30).

Recent RNA-modification research also demonstrates that superficially similar SAM-dependent RNA methyltransferases can have sharply different targets—for example, distinct enzymes install N2-methylguanosine at particular positions in human tRNAs and U6. This broader finding emphasizes why domain annotation alone cannot determine the substrate of NCU11362.

7. Current applications and real-world implementation

There is no identified industrial, clinical, agricultural, or biotechnological application specific to NCU11362. Its current practical value is as an uncharacterized functional-genomics target in a genetically tractable filamentous fungus.

Potential research applications include:

These are proposed research uses, not established implementations.

8. Quantitative evidence and evidence gaps

The principal relevant structural study resolved human METTL16 catalytic-domain structures at 1.9 Å in the apo state and 2.1 Å with SAH. The analyzed catalytic construct comprised residues 1–291. These data strongly establish the molecular architecture of human METTL16 but provide no quantitative evidence about A7UX10 (ruszkowska2018structuralinsightsinto pages 5-7, ruszkowska2018structuralinsightsinto pages 2-3).

For NCU11362 itself, the available study counts from the retrieved literature are:

These figures describe the search outcome, not proof that no unindexed or unpublished data exist.

A prudent expert annotation would be:

“Putative SAM-dependent RNA methyltransferase, METTL16/RlmF-like; substrate and cellular role unknown.”

It would be inappropriate at present to name the protein definitively as “U6 snRNA m6A methyltransferase,” “23S rRNA A1618 methyltransferase,” or “MAT2A mRNA methyltransferase.” The human structural study itself notes that substrate recognition involves elements beyond the catalytic core and that RNA specificity cannot be inferred solely from the shared fold (ruszkowska2018structuralinsightsinto pages 3-5, ruszkowska2018structuralinsightsinto pages 7-9, ruszkowska2018structuralinsightsinto pages 10-11).

Highest-priority validation experiments

  1. Sequence and structure analysis: verify the NPPF-like catalytic region, SAM-binding residues, full domain boundaries, signal peptide/transmembrane absence, and nuclear or mitochondrial targeting sequences.
  2. Genetics: construct an NCU11362 deletion or conditional strain and perform complementation with wild-type and catalytic-site mutants.
  3. Localization: express a native-promoter fluorescent fusion and compare nucleoplasm, nucleolus, mitochondria, and cytosol.
  4. RNA-target discovery: perform UV-crosslinking/RIP sequencing or CLIP, followed by targeted testing of U6, rRNA, and enriched transcripts.
  5. Modification mapping: compare wild type and mutant using LC–MS/MS and nucleotide-resolution m6A methods; disappearance of a defined RNA modification in the mutant would be decisive.
  6. Biochemistry: assay purified A7UX10 with SAM and candidate RNAs, measure SAH formation and methyl incorporation, and identify the modified nucleotide by mass spectrometry.

Key sources

Bottom line

NCU11362/A7UX10 is correctly identified as the specified N. crassa protein, and its domain architecture supports a methyltransferase-family assignment. Nevertheless, its primary function remains predicted rather than demonstrated. The leading hypothesis is SAM-dependent methylation of an adenosine in structured RNA, but the actual RNA species, nucleotide position, cellular compartment, and biological pathway cannot presently be resolved between METTL16-like and RlmF-like alternatives.

References

  1. (ruszkowska2018structuralinsightsinto pages 5-7): Agnieszka Ruszkowska, Milosz Ruszkowski, Zbigniew Dauter, and Jessica A. Brown. Structural insights into the rna methyltransferase domain of mettl16. Scientific Reports, Mar 2018. URL: https://doi.org/10.1038/s41598-018-23608-8, doi:10.1038/s41598-018-23608-8. This article has 132 citations and is from a peer-reviewed journal.

  2. (ruszkowska2018structuralinsightsinto pages 3-5): Agnieszka Ruszkowska, Milosz Ruszkowski, Zbigniew Dauter, and Jessica A. Brown. Structural insights into the rna methyltransferase domain of mettl16. Scientific Reports, Mar 2018. URL: https://doi.org/10.1038/s41598-018-23608-8, doi:10.1038/s41598-018-23608-8. This article has 132 citations and is from a peer-reviewed journal.

  3. (ruszkowska2018structuralinsightsinto pages 2-3): Agnieszka Ruszkowska, Milosz Ruszkowski, Zbigniew Dauter, and Jessica A. Brown. Structural insights into the rna methyltransferase domain of mettl16. Scientific Reports, Mar 2018. URL: https://doi.org/10.1038/s41598-018-23608-8, doi:10.1038/s41598-018-23608-8. This article has 132 citations and is from a peer-reviewed journal.

  4. (ruszkowska2018structuralinsightsinto pages 1-2): Agnieszka Ruszkowska, Milosz Ruszkowski, Zbigniew Dauter, and Jessica A. Brown. Structural insights into the rna methyltransferase domain of mettl16. Scientific Reports, Mar 2018. URL: https://doi.org/10.1038/s41598-018-23608-8, doi:10.1038/s41598-018-23608-8. This article has 132 citations and is from a peer-reviewed journal.

  5. (ruszkowska2018structuralinsightsinto pages 9-10): Agnieszka Ruszkowska, Milosz Ruszkowski, Zbigniew Dauter, and Jessica A. Brown. Structural insights into the rna methyltransferase domain of mettl16. Scientific Reports, Mar 2018. URL: https://doi.org/10.1038/s41598-018-23608-8, doi:10.1038/s41598-018-23608-8. This article has 132 citations and is from a peer-reviewed journal.

  6. (ruszkowska2018structuralinsightsinto pages 11-11): Agnieszka Ruszkowska, Milosz Ruszkowski, Zbigniew Dauter, and Jessica A. Brown. Structural insights into the rna methyltransferase domain of mettl16. Scientific Reports, Mar 2018. URL: https://doi.org/10.1038/s41598-018-23608-8, doi:10.1038/s41598-018-23608-8. This article has 132 citations and is from a peer-reviewed journal.

  7. (spagnuolo2024uncoveringthefunctions pages 4-6): Uncovering the functions of novel m6A and Nm writers in Drosophila melanogaster This article has 0 citations and is from a peer-reviewed journal.

  8. (spagnuolo2024uncoveringthefunctions pages 27-30): Uncovering the functions of novel m6A and Nm writers in Drosophila melanogaster This article has 0 citations and is from a peer-reviewed journal.

  9. (ruszkowska2018structuralinsightsinto pages 7-9): Agnieszka Ruszkowska, Milosz Ruszkowski, Zbigniew Dauter, and Jessica A. Brown. Structural insights into the rna methyltransferase domain of mettl16. Scientific Reports, Mar 2018. URL: https://doi.org/10.1038/s41598-018-23608-8, doi:10.1038/s41598-018-23608-8. This article has 132 citations and is from a peer-reviewed journal.

  10. (ruszkowska2018structuralinsightsinto pages 10-11): Agnieszka Ruszkowska, Milosz Ruszkowski, Zbigniew Dauter, and Jessica A. Brown. Structural insights into the rna methyltransferase domain of mettl16. Scientific Reports, Mar 2018. URL: https://doi.org/10.1038/s41598-018-23608-8, doi:10.1038/s41598-018-23608-8. This article has 132 citations and is from a peer-reviewed journal.

Artifacts

Citations

  1. ruszkowska2018structuralinsightsinto pages 9-10
  2. spagnuolo2024uncoveringthefunctions pages 4-6
  3. ruszkowska2018structuralinsightsinto pages 5-7
  4. ruszkowska2018structuralinsightsinto pages 3-5
  5. ruszkowska2018structuralinsightsinto pages 2-3
  6. ruszkowska2018structuralinsightsinto pages 1-2
  7. ruszkowska2018structuralinsightsinto pages 11-11
  8. spagnuolo2024uncoveringthefunctions pages 27-30
  9. ruszkowska2018structuralinsightsinto pages 7-9
  10. ruszkowska2018structuralinsightsinto pages 10-11
  11. https://doi.org/10.1038/s41598-018-23608-8
  12. https://doi.org/10.25358/openscience-10538
  13. https://doi.org/10.1038/s41598-018-23608-8,