wA encodes the polyketide synthase responsible for the first step of conidial green-pigment biosynthesis in Aspergillus nidulans. wA produces the naphthopyrone (YWA1) precursor of the conidial pigment; wA mutants form colorless (white) conidia. The pigment is subsequently modified by downstream enzymes including the conidial laccase yA to yield the mature green color.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0016491 oxidoreductase activity | IBA GO_REF:0000033 | MARK AS OVER ANNOTATED | Summary: Imprecise MF: wA is a polyketide synthase; a generic oxidoreductase term does not capture its activity. Reason: wA is a non-reducing polyketide synthase (KS, MAT, product-template, two ACP and Claisen-cyclase domains; no ketoreductase or enoylreductase domain per UniProt features) that synthesizes the naphthopyrone YWA1, so it has no identified oxidoreductase catalytic domain. The PAINT node (PTN002453893) is grounded on wA's own experimental row for GO:0052716 hydroquinone:oxygen oxidoreductase (laccase) activity (PMID:7050088), which this review judges to be a cross-attribution of the conidial laccase (yA) activity to wA. The oxidoreductase IBA therefore inherits a source-side problem rather than reflecting a phylogenetically inherited redox activity. Propagation Review Root cause: SOURCE BAD Failure modes: SOURCE MISCITATION ROLE CONFLATION Sources checked: PANTHER:PTN002453893 SOURCE BAD Node-level oxidoreductase assertion whose experimental grounding is the wA laccase IMP row; the laccase activity belongs to yA, and wA lacks reductive or oxidase domains. UniProtKB:Q03149 · wA SOURCE BAD The target's own GO:0052716 IMP annotation (PMID:7050088) is the descendant evidence; the cited abstract attributes laccase activity to the laccase structural gene and describes wA strains as lacking the laccase substrate. Proposed replacements: polyketide synthase activity |
| GO:0004315 3-oxoacyl-[acyl-carrier-protein] synthase activity | IEA GO_REF:0000002 | ACCEPT | Summary: Accept: 3-oxoacyl-[acyl-carrier-protein] synthase activity. Reason: The ketosynthase domain of the WA polyketide synthase. The term names the condensation step of polyketide chain extension, which is the catalytic core of the megasynthase. |
| GO:0006633 fatty acid biosynthetic process | IEA GO_REF:0000002 | MARK AS OVER ANNOTATED | Summary: Over-annotated: wA makes a polyketide pigment, not fatty acids. Reason: Propagated from fatty-acid-synthase homology; wA synthesizes the naphthopyrone pigment precursor, not fatty acids. Proposed replacements: pigment biosynthetic process |
| GO:0016740 transferase activity | IEA GO_REF:0000002 | KEEP AS NON CORE | Summary: Generic transferase-activity term. Reason: Root-level electronic term; uninformative for the PKS. |
| GO:0016746 acyltransferase activity | IEA GO_REF:0000002 | ACCEPT | Summary: Accept: acyltransferase activity. Reason: The acyltransferase domain that loads extender units onto the carrier protein; a constituent activity of the same megasynthase rather than an independent function. |
| GO:0031177 phosphopantetheine binding | IEA GO_REF:0000002 | ACCEPT | Summary: Accept: phosphopantetheine binding. Reason: The phosphopantetheine attachment site of the acyl-carrier domain. A cofactor/structural facet of the WA polyketide synthase, not a separate biological role. |
| GO:0046148 pigment biosynthetic process | IEA GO_REF:0000117 | ACCEPT | Summary: Accept: pigment biosynthetic process. Reason: WA produces the polyketide precursor of the conidial green pigment, so a pigment-biosynthesis process term is correct; the developmental-pigmentation term below is the more specific statement. |
| GO:0019748 secondary metabolic process | NAS PMID:22228366 Advances in Aspergillus secondary metabolite research in the... | ACCEPT | Summary: Accept: secondary metabolic process. Reason: Author statement in a review of Aspergillus secondary metabolism. Correct in that a polyketide product is a secondary metabolite, but NAS from a review article is the weakest evidence line here and the term is very general. |
| GO:0052716 hydroquinone:oxygen oxidoreductase activity | IMP PMID:7050088 Purification and characterization of the conidial laccase of... | REMOVE | Summary: Mis-attributed: laccase (hydroquinone:oxygen oxidoreductase) activity is that of the conidial laccase yA, not the PKS wA, and is contradicted by the cited paper itself. Reason: The cited paper (PMID:7050088) purifies the conidial laccase and states that laccase activity is absent "in a strain carrying a mutation in the structural gene for laccase" (yA), and that wA strains lack the laccase's substrate (the wA-derived pigment precursor) - i.e. wA supplies the substrate and is upstream of the laccase, it is not the laccase. Combined with wA being a polyketide synthase (PMID:1465094), the GO:0052716 activity is a wrong-enzyme cross-attribution to wA, not merely an over-broad annotation. This is a genuinely contradicted molecular function (the cited evidence refutes it), so REMOVE rather than MARK_AS_OVER_ANNOTATED. Supporting Evidence: PMID:7050088 Since wA strains lack the precursor of the wild-type green pigment, i.e., the laccase substrate |
| GO:0043324 pigment metabolic process involved in developmental pigmentation | IMP PMID:4624671 Absence of laccase from yellow-spored mutants of Aspergillus... | ACCEPT | Summary: Accept: pigment metabolic process involved in developmental pigmentation. Reason: The most informative process term in this set: the classic spore-colour mutant series ties the WA polyketide product specifically to conidial pigmentation rather than to secondary metabolism at large. |
| GO:0046148 pigment biosynthetic process | IMP PMID:1465094 The developmentally regulated Aspergillus nidulans wA gene e... | ACCEPT | Summary: Core process. wA is required for conidial pigment biosynthesis. Reason: wA is required for green-pigment synthesis; wA mutants have white conidia. Supporting Evidence: PMID:1465094 The Aspergillus nidulans wA gene is required for synthesis of a green pigment present in the walls of mature asexual spores (conidia); wA mutants produce colorless (white) conidia |
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