perinucleolar compartment

GO:0097356 · Ribonucleoprotein · Other · Proposed

The perinucleolar compartment (PNC) is a subnuclear structure associated with, but structurally distinct from, the nucleolus. The PNC contains large amounts of the heterogeneous nuclear ribonucleoprotein complex (hnRNP) called hnRNP I (PTB). Many RNA binding proteins as well as RNA polymerase III transcripts are highly enriched in this compartment. PTB and pol III transcripts are required for the integrity of the PNC. [GO:0097356]

Synonyms: perinucleolar region; PNC

Part of: nuclear lumen (GO:0031981)

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

Components

Component	Type	Part of / acts on	Grounding	Genes	Stoichiometry	Essential	Role
polypyrimidine tract-binding protein	Protein	part of	Reviewed label only (reviewed name; no accession asserted)			ESSENTIAL	RNA-binding protein concentrated in the PNC and required with RNA polymerase III transcripts to maintain PNC integrity. `DOI:10.1083/jcb.129.5.1181` Matera et al. 1995 identified hnRNP I/PTB as a protein concentrated in the perinucleolar compartment. `DOI:10.1091/mbc.E02-12-0818` Wang et al. 2003 showed that PTB and RNA polymerase III transcripts are essential for perinucleolar compartment integrity.
RNA polymerase III transcript cohort	Rna	part of	Reviewed label only (reviewed name; no accession asserted)			ESSENTIAL	Pol III-transcribed RNAs concentrated in the PNC and required with PTB for visible PNC integrity. `DOI:10.1083/jcb.129.5.1181` Matera et al. 1995 found human Y RNAs, RNase P RNA and RNase MRP RNA colocalized in perinucleolar compartments. `DOI:10.1091/mbc.E02-12-0818` Wang et al. 2003 showed that RNA polymerase III transcripts and PTB are essential for PNC integrity.

Taxonomic distribution

NCBITaxon:9606 Homo sapiens — VARIABLE: Human cultured cells were used to define the PNC as a perinucleolar focus enriched in PTB and RNA polymerase III transcripts. [DOI:10.1083/jcb.129.5.1181]

Canonical examples

NCBITaxon:9606 Homo sapiens — HeLa-derived human cells were used to identify Y RNAs, RNase P RNA, RNase MRP RNA and hnRNP I/PTB within the perinucleolar compartment. [DOI:10.1083/jcb.129.5.1181]

Functions

RNA polymerase III RNP compartment organization — Perinucleolar compartments concentrate PTB and multiple RNA polymerase III transcripts in a dynamic subnuclear structure associated with the nucleolus.
- DOI:10.1083/jcb.129.5.1181 Matera et al. 1995 described the PNC as a subnuclear compartment containing several RNA polymerase III transcripts and hnRNP I/PTB.
- DOI:10.1083/jcb.137.5.965 Huang et al. 1997 analyzed the dynamic organization of the perinucleolar compartment in the cell nucleus.

Mechanism graphs

PTB and pol III RNAs organize the PNC (ASSEMBLY)

Human perinucleolar compartments concentrate polypyrimidine tract-binding protein together with several RNA polymerase III transcripts, and both classes are needed for visible PNC integrity.

Subject	Predicate	Object	Evidence
polypyrimidine tract-binding protein	localizes to	perinucleolar compartment	`DOI:10.1083/jcb.129.5.1181` Matera et al. 1995 localized hnRNP I/PTB to perinucleolar compartments.
RNA polymerase III transcript cohort	localize to	perinucleolar compartment	`DOI:10.1083/jcb.129.5.1181` Matera et al. 1995 identified several pol III transcripts in PNCs, including Y RNAs, RNase P RNA and RNase MRP RNA.
polypyrimidine tract-binding protein	supports integrity of	perinucleolar compartment	`DOI:10.1091/mbc.E02-12-0818` Wang et al. 2003 tested PTB and RNA polymerase III transcripts as requirements for PNC integrity.
RNA polymerase III transcript cohort	support integrity of	perinucleolar compartment	`DOI:10.1091/mbc.E02-12-0818` Wang et al. 2003 tested PTB and RNA polymerase III transcripts as requirements for PNC integrity.

Discussions

CURATION_TODO (OPEN): Resolve exact source-neutral RNA and protein-family boundaries for PTB, Y RNAs, RNase P RNA, RNase MRP RNA and other PNC-enriched RNA-binding proteins. This first perinucleolar-compartment record captures PTB and PNC-enriched RNA polymerase III transcripts as label-only resident components while leaving exact PTB family grounding and transcript-class splitting to a later curation pass.

Evidence

GO:0097356 Gene Ontology cellular-component term for perinucleolar compartment and its exact perinucleolar-region synonym.
GO:0031981 Gene Ontology cellular-component term for nuclear lumen and GO:0097356 parthood target.
DOI:10.1083/jcb.129.5.1181 Matera, Frey, Margelot and Wolin 1995, A perinucleolar compartment contains several RNA polymerase III transcripts as well as the polypyrimidine tract-binding protein, hnRNP I, Journal of Cell Biology.
DOI:10.1083/jcb.137.5.965 Huang, Deerinck, Ellisman and Spector 1997, The Dynamic Organization of the Perinucleolar Compartment in the Cell Nucleus, Journal of Cell Biology.
DOI:10.1091/mbc.E02-12-0818 Wang, Politz, Pederson and Huang 2003, RNA Polymerase III Transcripts and the PTB Protein Are Essential for the Integrity of the Perinucleolar Compartment, Molecular Biology of the Cell.
DOI:10.1101/cshperspect.a000679 Pollock and Huang 2010, The Perinucleolar Compartment, Cold Spring Harbor Perspectives in Biology.

Curation history

2026-09-28T02:09:01Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-28T02:10:16Z codex · EXPANDED_RECORD — Added perinucleolar-compartment synonymy, nuclear-lumen parthood, label-only PTB and RNA polymerase III transcript components, Homo sapiens scope, DOI/GO evidence, a nonmechanistic PTB/pol III RNA organization graph and a component-boundary TODO.
2026-09-28T02:22:00Z codex · TIGHTENED_GRAPH — Split the PTB/pol III transcript integrity edge into direct PTB-to-PNC and pol III RNA-to-PNC integrity edges.
2026-09-28T02:22:36Z codex · NORMALIZED_YAML — Normalized the duplicated PNC-integrity graph evidence lists so the record emits without YAML aliases.
2026-09-28T02:37:03Z codex · RESOLVED_REVIEW — Resolved #1697 by correcting the inherited hnRNP 1 typo in the perinucleolar compartment definition to hnRNP I.

Source: data/structures/ribonucleoprotein/perinucleolar_compartment.yaml