FB2026_03 , released September 17, 2026

CV Term Report

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General Information

Term

facultative heterochromatin formation

ID (Ontology)

GO:0140718 (Gene Ontology)

Definition

The compaction of chromatin into a conformation that is refractory to transcription but that can be converted to euchromatin and allow transcription in specific contexts. These can be temporal (e.g., developmental states or specific cell-cycle stages), spatial (e.g., nuclear localization changes from the center to the periphery or vice versa due to exogenous factors/signals), or parental/heritable (e.g., monoallelic gene expression). In metazoa, this involves the methylation of histone H3K27, and in certain cases methylation of H3K9. On the other hand, in unicellular eukaryotes, only methylation of H3K9 is involved and H3K27 is not methylated.[ PubMed:17936700 ]

Also Known As

"facultative heterochromatin assembly" ; "fHC assembly"

Comment

Links to External Ontologies

QuickGO data AmiGO data

Annotations

Records annotated with this term OR any of its CHILD TERMS

Choose a record type to view annotations for this term and its child terms. Direct annotations and full annotation statements below also provide HitList buttons.

Results list data from multiple species. Choose a record type above to open its HitList.

Direct annotations: records annotated with this exact term (child terms are NOT included)

Data Class	Field	Direct annotations
Genes (FBgn)	GO_BIOLOGICAL_PROCESS

Full annotation statements including this term (annotations to child terms are NOT included), and relevant FlyBase records

Full annotation statements	Relevant FlyBase reports
Full annotation statements	Genes
facultative heterochromatin formation (all annotations which use CV term, excluding "NOT" statements)
involved_in \| facultative heterochromatin formation

Spanning Tree (Parents/Children)

cellular component assembly_________________________
negative regulation of gene expression, epigenetic__|
heterochromatin organization________________________|
                                                    heterochromatin formation
                                                     |__facultative heterochromatin formation  8 rec.
                                                         |__rDNA heterochromatin formation 2 rec.
                                                         |   |__regulation of rDNA heterochromatin formation(+)
                                                         |__siRNA-independent facultative heterochromatin formation
                                                         |   |__regulation of siRNA-independent facultative heterochromatin formation
                                                         |__siRNA-mediated facultative heterochromatin formation
                                                             |__regulation of siRNA-mediated facultative heterochromatin formation

Spanning Tree View Settings
Parents/Children View Depth	Show hierarchy levels: for parents, for children
Relationships
Is a	heterochromatin formation
Part of
Synonyms & Secondary IDs
Synonyms
	"facultative heterochromatin assembly" EXACT "fHC assembly" EXACT
Secondary IDs

External Crossreferences & Linkouts