NCGR_LOCUS10166

UniProt ID: A0A811MX19
Organism: Miscanthus lutarioriparius
Review Status: IN PROGRESS
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Gene Description

NCGR_LOCUS10166 encodes a predicted 719-amino-acid protein in Miscanthus lutarioriparius with an N-terminal histidinol dehydrogenase-like domain and a C-terminal ARV1-like membrane region. The HDH domain retains annotated catalytic and zinc-binding residues and is strongly conserved relative to a separate Miscanthus HDH, supporting a role in NAD-dependent histidinol oxidation during histidine biosynthesis. The ARV-like region suggests a connection to membrane lipid homeostasis. Whether the deposited model produces a single functional fusion protein, and how its domains are processed or targeted between plastid and endomembrane compartments, remain unresolved.

Existing Annotations Review

GO Term Evidence Action Reason
GO:0004399 histidinol dehydrogenase activity
IEA
GO_REF:0000120 		ACCEPT
Summary: The retained HDH catalytic domain supports the inferred enzyme activity.
Reason: The candidate preserves E368/H369 and Q300/H303/D402/H461 and has 460/472 identities across the aligned HDH region. UniProt missing-residue caution cites ARV1 rule RU368065, not HDH. A plausible fusion-model error does not demonstrate catalytic loss; retain the domain-based inference with the gene-model limitation recorded separately.
Propagation Review
Root cause: NO FAILURE CORE
Supporting Evidence:
file:9POAL/NCGR_LOCUS10166/NCGR_LOCUS10166-bioinformatics/RESULTS.md
Both deposited CDD annotations identify catalytic E368/H369 and zinc-site Q300/H303/D402/H461, and the actual candidate sequence retains these residues.
GO:0016491 oxidoreductase activity
IEA
GO_REF:0000002 		ACCEPT
Summary: The HDH domain supports oxidoreductase activity.
Reason: This existing InterPro inference is consistent with the strongly conserved HDH domain and retained catalytic residues. A valid broad parent is not an over-annotation simply because a more specific enzyme term coexists.
Supporting Evidence:
file:9POAL/NCGR_LOCUS10166/NCGR_LOCUS10166-bioinformatics/RESULTS.md
Both deposited CDD annotations identify catalytic E368/H369 and zinc-site Q300/H303/D402/H461, and the actual candidate sequence retains these residues.
GO:0016616 oxidoreductase activity, acting on the CH-OH group of donors, NAD or NADP as acceptor
IEA
GO_REF:0000002 		ACCEPT
Summary: The HDH-like domain supports NAD-dependent alcohol oxidation.
Reason: The inferred histidinol oxidation chemistry falls within this term. Retained active-site residues and strong sequence conservation support the mapping; no target-specific loss is established.
Supporting Evidence:
file:9POAL/NCGR_LOCUS10166/NCGR_LOCUS10166-bioinformatics/RESULTS.md
Both deposited CDD annotations identify catalytic E368/H369 and zinc-site Q300/H303/D402/H461, and the actual candidate sequence retains these residues.
GO:0046872 metal ion binding
IEA
GO_REF:0000002 		ACCEPT
Summary: The HDH domain retains the annotated zinc-coordination residues.
Reason: Q300/H303/D402/H461 are retained in the candidate and the separate HDH model. Accept metal binding based on the HDH domain; no ARV zinc-binding claim is needed, and broad specificity alone is not false.
Supporting Evidence:
file:9POAL/NCGR_LOCUS10166/NCGR_LOCUS10166-bioinformatics/RESULTS.md
Both deposited CDD annotations identify catalytic E368/H369 and zinc-site Q300/H303/D402/H461, and the actual candidate sequence retains these residues.
GO:0051287 NAD binding
IEA
GO_REF:0000002 		ACCEPT
Summary: NAD binding is supported by the conserved HDH domain.
Reason: The HDH domain and annotated NAD-binding region are present. This source mapping is compatible with the inferred reaction; it is not invalidated by coexistence of the enzyme annotation or an unproven fusion-model problem.
Supporting Evidence:
file:9POAL/NCGR_LOCUS10166/NCGR_LOCUS10166-bioinformatics/RESULTS.md
Both deposited CDD annotations identify catalytic E368/H369 and zinc-site Q300/H303/D402/H461, and the actual candidate sequence retains these residues.
GO:0000105 L-histidine biosynthetic process
IEA
GO_REF:0000120 		ACCEPT
Summary: The inferred HDH domain catalyzes the final histidine-biosynthetic oxidation.
Reason: Retain the pathway inference attached to conserved HDH catalysis. This product would perform the biosynthetic reaction, rather than merely be its substrate. Localization and whether the fusion model is expressed remain separate uncertainties.
Supporting Evidence:
file:9POAL/NCGR_LOCUS10166/NCGR_LOCUS10166-bioinformatics/RESULTS.md
Both deposited CDD annotations identify catalytic E368/H369 and zinc-site Q300/H303/D402/H461, and the actual candidate sequence retains these residues.
GO:0006665 sphingolipid metabolic process
IEA
GO_REF:0000104 		UNDECIDED
Summary: An ARV-like region supports a lipid-homeostasis hypothesis whose target-specific scope is unresolved.
Reason: The previous categorical artifact premise was unproved. The ARV region is substantially conserved but has divergent ends and an ARV-specific feature-propagation caution. PMID:16725371 reports tolerated deletion of the cysteine-rich subdomain, so missing cysteines do not establish inactivity. Full-domain function, model validity and a direct sphingolipid role need adjudication.
Supporting Evidence:
file:9POAL/NCGR_LOCUS10166/NCGR_LOCUS10166-bioinformatics/RESULTS.md
Distinct domain functions and organelle destinations are not by themselves proof of a gene-model error.
GO:0016125 sterol metabolic process
IEA
GO_REF:0000104 		UNDECIDED
Summary: ARV-dependent sterol homeostasis is plausible but not resolved for this predicted fusion.
Reason: Homolog evidence supports ARV biology; sequence divergence and the fusion-model uncertainty require assessment rather than blanket rejection. The ARV-specific caution does not demonstrate complete functional loss, and the separate chromosome-1 gene does not prove the chromosome-2 model is false.
Supporting Evidence:
file:9POAL/NCGR_LOCUS10166/NCGR_LOCUS10166-bioinformatics/RESULTS.md
Distinct domain functions and organelle destinations are not by themselves proof of a gene-model error.
GO:0032366 intracellular sterol transport
IEA
GO_REF:0000120 		MARK AS OVER ANNOTATED
Summary: The inherited ARV-family sterol-transport assignment is too direct.
Reason: The focused OpenScientist report separated direct sterol transport from the broader membrane and lipid-homeostasis phenotypes of ARV deficiency. Georgiev et al. directly tested retrograde and anterograde sterol traffic in yeast arv1 mutants and found normal ER-plasma membrane transport, making this specific ARV UniRule propagation stronger than the available mechanistic evidence. The Miscanthus ARV-like region and gene model also remain unresolved, so no target-specific assay rescues the direct transport claim.
Supporting Evidence:
PMID:23668914
We report that sterol transport between the ER and PM is unaffected by Arv1 deficiency.
file:9POAL/NCGR_LOCUS10166/NCGR_LOCUS10166-hypotheses/fusion-model-arv-function-and-targeting/openscientist.md
removing or generalizing GO:0032366 (intracellular sterol transport)
file:9POAL/NCGR_LOCUS10166/NCGR_LOCUS10166-bioinformatics/RESULTS.md
Distinct domain functions and organelle destinations are not by themselves proof of a gene-model error.
GO:0097036 regulation of plasma membrane sterol distribution
IEA
GO_REF:0000104 		UNDECIDED
Summary: ARV-dependent plasma membrane sterol distribution is plausible but not resolved for this predicted fusion.
Reason: Yeast Arv1 deficiency changes plasma membrane sterol availability and lipid asymmetry, so PMID:23668914 supports a broader membrane-homeostasis role rather than refuting sterol distribution the way it refutes direct ER-plasma membrane sterol transport. However, the candidate Miscanthus ARV-like region is part of a probable HDH-ARV gene-model merge and has no target-specific membrane assay, leaving this ARV-derived process on the same unresolved footing as the inherited sterol- and sphingolipid-metabolism rows.
Supporting Evidence:
PMID:23668914
Arv1-deficient cells show defects in cortical and cytoplasmic ER, and changes in the lipid organization of the PM such that sterol ‘availability’ increases and the transbilayer asymmetry of the PM phospholipid bilayer is altered.
file:9POAL/NCGR_LOCUS10166/NCGR_LOCUS10166-hypotheses/fusion-model-arv-function-and-targeting/openscientist.md
if retained, restate as lipid/membrane-homeostasis and mark **non-core, IEA-only**.
file:9POAL/NCGR_LOCUS10166/NCGR_LOCUS10166-bioinformatics/RESULTS.md
Distinct domain functions and organelle destinations are not by themselves proof of a gene-model error.
GO:0005737 cytoplasm
IEA
GO_REF:0000118 		ACCEPT
Summary: The broad cytoplasmic compartment is compatible with the predicted protein architecture.
Reason: Both plastids and the endoplasmic reticulum are cytoplasmic organelles. The previous reasoning wrongly treated cytoplasm as equivalent to cytosol and used unresolved organelle targeting to reject a broad TreeGrafter inference. The UniProt compartment/architecture assignment is electronic supporting evidence, not a target localization assay; the sequence retains the ARV-like region despite uncertainty about its full physiology.
Supporting Evidence:
file:9POAL/NCGR_LOCUS10166/NCGR_LOCUS10166-uniprot.txt
Plastid, chloroplast
GO:0005783 endoplasmic reticulum
IEA
GO_REF:0000117 		UNDECIDED
Summary: An ER destination is plausible for the ARV-like membrane region.
Reason: Arabidopsis ARV localization supports this possibility but does not determine targeting of the complete fusion. Conversely, an HDH-like N-terminus does not prove that ER localization is impossible. Model structure, processing and targeting remain unresolved.
Supporting Evidence:
file:9POAL/NCGR_LOCUS10166/NCGR_LOCUS10166-bioinformatics/RESULTS.md
Distinct domain functions and organelle destinations are not by themselves proof of a gene-model error.
GO:0005789 endoplasmic reticulum membrane
IEA
GO_REF:0000120 		UNDECIDED
Summary: The ARV-like region supports membrane insertion, but the particular membrane is uncertain.
Reason: Conserved hydrophobic segments support membrane association. Assignment specifically to ER membrane depends on the full gene product and targeting; chloroplast predictions alone do not refute it.
Supporting Evidence:
file:9POAL/NCGR_LOCUS10166/NCGR_LOCUS10166-bioinformatics/RESULTS.md
Distinct domain functions and organelle destinations are not by themselves proof of a gene-model error.
GO:0005829 cytosol
IEA
GO_REF:0000118 		UNDECIDED
Summary: A soluble cytosolic pool is not established or excluded.
Reason: The sequence includes a plant HDH-like N-terminus and a hydrophobic ARV-like region. Neither predicted organelle targeting nor possible gene-model fusion proves exclusive localization. The exact TreeGrafter source placement and target processing require adjudication.
Supporting Evidence:
file:9POAL/NCGR_LOCUS10166/NCGR_LOCUS10166-bioinformatics/RESULTS.md
Distinct domain functions and organelle destinations are not by themselves proof of a gene-model error.
GO:0009507 chloroplast
IEA
GO_REF:0000044 		UNDECIDED
Summary: A chloroplast destination is plausible from the plant HDH-like N-terminus.
Reason: The N-terminus is strongly conserved with a separate predicted plant HDH. A C-terminal membrane region does not categorically preclude plastid import or processing, but no target localization or authentic fusion transcript has been established.
Supporting Evidence:
file:9POAL/NCGR_LOCUS10166/NCGR_LOCUS10166-bioinformatics/RESULTS.md
Distinct domain functions and organelle destinations are not by themselves proof of a gene-model error.
GO:0009570 chloroplast stroma
IEA
GO_REF:0000118 		UNDECIDED
Summary: Chloroplast-stroma localization remains a plausible HDH-associated inference.
Reason: The strong HDH-like N-terminus supports the ancestral localization, while the fused membrane region raises a real targeting question. Rejecting stroma solely because another domain predicts ER localization assumed exclusivity and model error without evidence.
Supporting Evidence:
file:9POAL/NCGR_LOCUS10166/NCGR_LOCUS10166-bioinformatics/RESULTS.md
Distinct domain functions and organelle destinations are not by themselves proof of a gene-model error.
GO:0016020 membrane
IEA
GO_REF:0000104 		ACCEPT
Summary: The ARV-like C-terminal region retains strongly hydrophobic membrane segments.
Reason: Broad membrane association is supported by the actual candidate sequence. It is not an over-annotation merely because specific membranes were also predicted; exact ER versus plastid targeting remains unresolved. The UniProt compartment/architecture assignment is electronic supporting evidence, not a target localization assay; the sequence retains the ARV-like region despite uncertainty about its full physiology.
Supporting Evidence:
file:9POAL/NCGR_LOCUS10166/NCGR_LOCUS10166-uniprot.txt
pass membrane protein {ECO:0000256|ARBA:ARBA00004477,

Core Functions

The conserved N-terminal HDH domain is predicted to catalyze NAD-dependent oxidation of histidinol to histidine. Annotated catalytic and zinc-coordination residues are retained. This is an inference from the deposited model; expression of a complete fusion and its physiological compartment remain unresolved.

Molecular Function:
histidinol dehydrogenase activity
Directly Involved In:
L-histidine biosynthetic process
Supporting Evidence:
  • file:9POAL/NCGR_LOCUS10166/NCGR_LOCUS10166-bioinformatics/RESULTS.md
    Both deposited CDD annotations identify catalytic E368/H369 and zinc-site Q300/H303/D402/H461, and the actual candidate sequence retains these residues.

References

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Suggested Questions for Experts

Q: Does Ml02G067130.1 encode an expressed fusion, alternative processed products, or an incorrectly merged model? Deposited chromosome-1 homolog coordinates establish a separate adjacent pair, but do not resolve the chromosome-2 transcript.

Q: Does the candidate ARV region retain the functional AHD C-terminal subdomain and lipid-homeostasis roles despite divergent ends? Loss of the cysteine-rich subdomain alone is tolerated in Arabidopsis.

Q: What are the mature products and destinations, and can a soluble cytosolic pool or plastid/ER partitioning be demonstrated?

Suggested Experiments

Experiment: Sequence full-length transcripts across the proposed HDH–ARV junction and test protein termini with targeted proteomics.

Hypothesis: The locus may generate a fusion, separate products or alternative transcripts; junction and peptide data can distinguish these possibilities.

Experiment: Assay HDH activity and ARV complementation for experimentally validated products, with organelle-localization imaging.

Hypothesis: The HDH domain may remain catalytically active even if the fused model or ARV targeting differs from the deposited prediction.

Tags

fusion-protein plant gene-model-uncertainty

Deep Research

Manual

(NCGR_LOCUS10166-deep-research-manual.md)

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OpenScientist

(NCGR_LOCUS10166-hypotheses/fusion-model-arv-function-and-targeting/openscientist.md)

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📚 Additional Documentation

Notes

(NCGR_LOCUS10166-notes.md)

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Bioinformatics Results

(RESULTS.md)

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📄 View Raw YAML

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