Gene Description

fl (fluffy) is the central regulator of asexual sporulation (macroconidiation) in Neurospora crassa. It encodes a Gal4-type binuclear Zn(II)2Cys6 zinc-cluster transcription factor that is necessary and sufficient to induce conidiation; fl-null strains grow as undifferentiated 'fluffy' aerial hyphae. FL directly activates developmentally regulated targets (including the eas/ccg-2 hydrophobin gene) and acts with the stage genes acon-2 and acon-3. FL is the functional analog of the Aspergillus BrlA master-switch role, but the two are non-orthologous.

Existing Annotations Review

GO Term	Evidence	Action	Reason
GO:0000981 DNA-binding transcription factor activity, RNA polymerase II-specific	IEA GO_REF:0000002	ACCEPT	Summary: Accept: DNA-binding transcription factor activity, RNA polymerase II-specific. Reason: Pol II-specific TF activity predicted from the Zn(II)2Cys6 binuclear cluster, and consistent with FL being both necessary and sufficient to induce conidiophore development.
GO:0005634 nucleus	IEA GO_REF:0000044	ACCEPT	Summary: Accept: nucleus. Reason: Nuclear location as the transcriptional role requires. Predicted only - no direct FL localisation is cited in this review.
GO:0006355 regulation of DNA-templated transcription	IEA GO_REF:0000002	ACCEPT	Summary: Accept: regulation of DNA-templated transcription. Reason: Generic regulation parent. FL's demonstrated activity is direct activation of a developmentally regulated target, which the Pol II term below captures more precisely.
GO:0006357 regulation of transcription by RNA polymerase II	IEA GO_REF:0000108	ACCEPT	Summary: Accept: regulation of transcription by RNA polymerase II. Reason: The Pol II-specific term, matching FL's direct activation of a developmentally regulated promoter. The most informative process term in this entirely electronic set.
GO:0008270 zinc ion binding	IEA GO_REF:0000002	ACCEPT	Summary: Accept: zinc ion binding. Reason: Zinc is structural to the binuclear-cluster DNA-binding domain; a real cofactor requirement rather than an independent function.
GO:0048315 conidium formation	IMP PMID:15126394 The fluffy gene of Neurospora crassa is necessary and suffic...	NEW	Summary: Proposed new annotation. Induction of macroconidiation is FL's defining role, yet GOA carries only generic electronic transcription-factor, zinc-binding and nuclear terms and no conidiation process term. Reason: Bailey-Shrode and Ebbole establish fl as necessary and sufficient to induce conidiophore development - raising fl expression from a heterologous promoter in a wild-type background induces conidiophores. The GOA set is entirely electronic (GO_REF) and captures only the generic machinery of transcription, leaving the process FL actually controls unannotated. GO:0048315 is the term core_functions already asserts for this gene, and the term GOA carries (IMP, acts_upstream_of_or_within) for the functionally analogous Aspergillus master regulators brlA and abaA reviewed in this module. Supporting Evidence: PMID:15126394 The fl (fluffy) gene of Neurospora crassa encodes a binuclear zinc cluster protein that regulates the production of asexual spores called macroconidia. PMID:15126394 Increasing expression of fl from a heterologous promoter in a wild-type genetic background is sufficient to induce conidiophore development.

Core Functions

Master transcriptional activator of macroconidiation: FL is a Gal4-type Zn(II)2Cys6 DNA-binding transcription factor, necessary and sufficient to induce conidiation, that directly activates developmentally regulated target genes.

Molecular Function:

DNA-binding transcription factor activity, RNA polymerase II-specific

Directly Involved In:

conidium formation

Cellular Locations:

nucleus

Supporting Evidence:

PMID:15126394
The fl (fluffy) gene of Neurospora crassa encodes a binuclear zinc cluster protein that regulates the production of asexual spores called macroconidia.
PMID:15126394
Increasing expression of fl from a heterologous promoter in a wild-type genetic background is sufficient to induce conidiophore development.
PMID:15773996
The fluffy (fl) gene of Neurospora crassa is required for asexual sporulation and encodes an 88 kDa polypeptide containing a typical fungal Zn2Cys6

References

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📚 Additional Documentation

Notes

(fl-notes.md)

fl / fluffy (Neurospora crassa) — curation notes

UniProt O13360. Gal4-type Zn(II)2Cys6 master TF of macroconidiation. Neurospora variant, master-activation tier.
- Necessary and sufficient for conidiation; binuclear zinc-cluster protein. [PMID:15126394 "The fluffy gene of Neurospora crassa is necessary and sufficient to induce conidiophore development"; "encodes a binuclear zinc cluster protein that regulates the production of asexual spores called macroconidia"].
- Major conidiation regulator; directly activates a hydrophobin (eas) gene. PMID:15773996.
- GOA only has IEA TF terms (all ACCEPT); the conidiation master-regulator role is proposed in core_functions (functional analog of Aspergillus BrlA, non-orthologous).

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