endospore-forming forespore

GO:0042601 · Spore · Subcellular region · Proposed

Portion of the cell formed during the process of bacterial sporulation that will ultimately become the core of the endospore. An endospore is a type of dormant cell that is resistant to adverse conditions. [GO:0042601]

Synonyms: forespore; prespore

Xrefs: uniprot.location:SL-0119 — Forespore

UniProt location names: UniProt Consortium, CC BY 4.0. Reference label and route sources.

Taxonomic distribution

NCBITaxon:1239 Bacillota — COMMON: Endospore-forming forespores occur as transient daughter compartments in endospore-forming Bacillota lineages during sporulation, with many non-sporulating members of the phylum lacking the structure. [DOI:10.1038/nrmicro2921]

Canonical examples

NCBITaxon:1423 Bacillus subtilis — Classical endospore model in which an asymmetric polar septum creates a smaller forespore compartment and a larger mother-cell compartment. [DOI:10.1038/nrmicro2921]

Mechanism graphs

Asymmetric septation creates the forespore (ASSEMBLY)

During Bacillus subtilis sporulation, polar septation partitions the developing cell into a small forespore compartment and a larger mother-cell compartment.

Subject	Predicate	Object	Evidence
asymmetric polar septum	delimits	endospore-forming forespore	`uniprot.location:SL-0119` — Forespore UniProt SL-0119 describes sporulation as forming an asymmetrically positioned septum that divides the developing cell into forespore and mother-cell compartments. `DOI:10.1016/j.cub.2005.02.041` Ramamurthi and Losick 2005 review protein localization to the Bacillus subtilis forespore during sporulation.

Discussions

INTERPRETATION (RESOLVED): Keep the bacterial forespore separate from the broader intracellular immature spore and from ascospore-type prospore records. GO:0042601 specifically denotes the bacterial sporulation compartment that becomes an endospore core, whereas GO:0042763 also parents fungal ascospore-type prospores and the existing GO:0005628 prospore membrane record is a yeast double-membrane structure.

Evidence

GO:0042601 Gene Ontology cellular-component term for the endospore-forming forespore.
GO:0042763 Gene Ontology cellular-component parent term for intracellular immature spores.
uniprot.location:SL-0119 — Forespore UniProt Subcellular Location entry SL-0119 identifies the bacterial Forespore location and maps it to GO:0042763.
DOI:10.1016/j.cub.2005.02.041 Ramamurthi and Losick 2005, Protein Localization: Reach out and Touch the Forespore, Current Biology.
DOI:10.1038/nrmicro2921 McKenney, Driks and Eichenberger 2012, The Bacillus subtilis endospore: assembly and functions of the multilayered coat, Nature Reviews Microbiology.

Curation history

2026-09-22T22:36:58Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-22T22:38:28Z codex · EXPANDED_RECORD — Added forespore synonyms, the intracellular immature spore parent, the UniProt SL cross-reference, Bacillota distribution, a Bacillus subtilis example, GO/UniProt/literature evidence, a nonmechanistic asymmetric-septation graph, and a bacterial-versus-ascospore boundary discussion.
2026-09-22T22:50:32Z codex · ADDRESS_REVIEW — Resolved #1330 by citing the Bacillus endospore review for the Bacillus subtilis canonical example and resolved #1331 by relaxing over-specific SpoII protein names in the graph scope note.

Source: data/structures/spore/endospore_forming_forespore.yaml