RNP body

GO:0140365 · Ribonucleoprotein · Other · Proposed

A ribonucleoprotein granule located in the cytoplasm of bacteria, minimally containing the RNase E protein and RNA molecules. Bacterial RNP-bodies are similar to eukaryotic P-bodies and stress granules. [GO:0140365]

Synonyms: BR-body; bacterial RNP body

Part of: GO:0005737 — cytoplasm (no local record)

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

Components

Component	Type	Part of / acts on	Grounding	Genes	Essential	Role
Ribonuclease E	Protein	part of	`InterPro:IPR028878`	rne	ESSENTIAL	Core scaffold in Caulobacter: its disordered C-terminal domain supports condensation with RNA and recruits degradosome clients; its catalytic domain cleaves RNA. Family membership alone does not establish BR-body formation in other bacteria. `DOI:10.1016/j.molcel.2018.08.003` CTD deletion disperses RNase E; CTD-only constructs form condensates. RNase E depletion disperses RhlB and aconitase foci. Assembly essentiality refers to this scaffold, not a requirement for its catalytic domain. `InterPro:IPR028878` Verified Ribonuclease E family, rather than the broader RNase E/G family; UniProt maps the experimentally used CCNA_01954 product to it.
mRNA	Rna	part of	`SO:0000234`		CONDITIONAL	RNA cargo and assembly substrate. Long, poorly translated mRNAs are preferentially enriched in the experimentally isolated Caulobacter bodies; the SO grounding denotes the RNA class, not this translation state. `DOI:10.1016/j.molcel.2018.08.003` In vivo mRNA depletion disperses bodies and rifampicin-resistant T7 transcription preserves them. Purified RNase E CTD can condense without RNA at suitable protein and salt concentrations, so mRNA is not asserted to be universally required in vitro. `DOI:10.1016/j.molcel.2020.04.001` RNA sequencing of active-site-mutant-stabilized bodies enriches mRNAs, small RNAs and antisense RNAs. Longer RNAs stimulate CTD droplet assembly in vitro; mRNA is not the only RNA class present.
RhlB RNA helicase	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	rhlB	DISPENSABLE	RNase E-recruited helicase client within Caulobacter BR-bodies. Loss of its RNase E binding site eliminates client foci without eliminating RNase E bodies. `DOI:10.1016/j.molcel.2018.08.003` Figure 3 and associated binding-site deletion experiments show RhlB co-localization and RNase E-dependent recruitment; the bodies persist when recruitment is disrupted.
aconitase	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	acnA	DISPENSABLE	RNase E-recruited metabolic-enzyme client in Caulobacter BR-bodies; its recruitment is dispensable for formation of the RNase E condensate. `DOI:10.1016/j.molcel.2018.08.003` Figure 3 shows aconitase co-localization with RNase E. Deleting the aconitase-binding site disperses aconitase while RNase E still forms bodies.

Organism-specific protein examples

Named proteins in which each component's role was established, with the organism the evidence comes from. The component above is the taxon-agnostic family; these are the specific entries behind it.

Ribonuclease E

Accession	Protein	Gene	Organism	Entry
`UniProtKB:A0A0H3CAR6`	Ribonuclease E	rne	Caulobacter vibrioides NA1000 (`NCBITaxon:565050`)	UNREVIEWED
Role and evidence (2 references) Experimentally tested BR-body scaffold and endoribonuclease. `UniProtKB:A0A0H3CAR6` UniProt identifies CCNA_01954 in taxon 565050; the accession is an unreviewed sequence mapping, not independent localization evidence. `DOI:10.1016/j.molcel.2018.08.003` Methods identify CCNA_01954 as the locus used for the experimentally localized fluorescent fusion.

RhlB RNA helicase

Accession	Protein	Gene	Organism	Entry
`UniProtKB:A0A0H3C8I9`	DEAD-box ATP-dependent RNA helicase RhpA	rhlB	Caulobacter vibrioides NA1000 (`NCBITaxon:565050`)	UNREVIEWED
Role and evidence (2 references) RhlB in the paper; UniProt currently labels the same locus RhpA while retaining the rhlB gene symbol. `UniProtKB:A0A0H3C8I9` UniProt identifies CCNA_01923 in taxon 565050; the accession is an unreviewed sequence mapping, not independent localization evidence. `DOI:10.1016/j.molcel.2018.08.003` Methods identify CCNA_01923 as the locus used for the experimentally localized fluorescent fusion.

aconitase

Accession	Protein	Gene	Organism	Entry
`UniProtKB:A0A0H3CE29`	Aconitate hydratase	acnA	Caulobacter vibrioides NA1000 (`NCBITaxon:565050`)	UNREVIEWED
Role and evidence (2 references) Aconitase client localized in RNase E-containing bodies. `UniProtKB:A0A0H3CE29` UniProt identifies CCNA_03781 in taxon 565050; the accession is an unreviewed sequence mapping, not independent localization evidence. `DOI:10.1016/j.molcel.2018.08.003` Methods identify CCNA_03781 as the locus used for the experimentally localized fluorescent fusion.

Canonical examples

NCBITaxon:565050 Caulobacter vibrioides NA1000 — All Caulobacter strains in the 2018 study derive from NA1000, historically called C. crescentus NA1000. Fluorescent-fusion imaging, RNase E domain and binding-site mutants, and RNA-depletion experiments establish BR-body assembly in this background. [DOI:10.1016/j.molcel.2018.08.003]

Functions

mRNA catabolic process GO:0006402 — During the assayed Caulobacter growth conditions, BR-bodies preferentially organize poorly translated mRNAs and decay enzymes, stimulating initial endonucleolytic cleavage and subsequent degradation. This does not assert identical RNA fate under every stress condition.
- DOI:10.1016/j.molcel.2020.04.001 Global half-life profiling and paired RNA-seq/qRT-PCR comparisons distinguish condensation-dependent initial cleavage from the contribution of recruited exoribonucleases to decay of intermediates.

Mechanism graphs

RNA-dependent condensation couples BR-body assembly to RNA cleavage (FUNCTION)

Caulobacter RNase E and available mRNA promote condensation; the resulting bodies stimulate RNA cleavage, which enables their dynamic disassembly.

Subject	Predicate	Object	Evidence
Ribonuclease E	drives	RNase E CTD-mediated condensation	`DOI:10.1016/j.molcel.2018.08.003` CTD deletion abolishes foci, CTD-only constructs form foci, and purified CTD forms salt- and concentration-dependent liquid-like droplets.
mRNA	promotes	RNase E CTD-mediated condensation	`DOI:10.1016/j.molcel.2018.08.003` Rifampicin/T7 experiments establish the cellular mRNA dependence; poly-A titrations promote droplets at intermediate RNA concentrations, while excess RNA inhibits condensation.
RNase E CTD-mediated condensation	forms	RNP body	`DOI:10.1016/j.molcel.2018.08.003` Live-cell fusion dynamics, RNase E domain perturbations and purified-protein phase behavior support the condensate interpretation.
Ribonuclease E	catalyzes	RNase E-mediated RNA cleavage	`DOI:10.1016/j.molcel.2018.08.003` Catalytically impaired RNase E and CTD-only replacements retain bodies but fail to support their normal rapid disassembly.
RNP body	stimulates	RNase E-mediated RNA cleavage	`DOI:10.1016/j.molcel.2020.04.001` qRT-PCR half-lives are prolonged in the noncondensing NTD mutant and partly restored by the condensation-competent degradosome-binding-site mutant, separating condensation from client recruitment.
RNase E-mediated RNA cleavage	enables	BR-body disassembly	`DOI:10.1016/j.molcel.2018.08.003` Wild-type bodies are dynamic on the minute scale; two catalytic mutants retain bodies throughout ten-minute imaging, and RNase A treatment dissolves stabilized bodies in lysates.

Discussions

CURATION_TODO (RESOLVED): Keep the BR-body condensate distinct from one RNA degradosome and from eukaryotic granules. The existing bacterial degradosome record describes a protein complex with an E. coli-centered component set. BR-bodies are mesoscale RNase E/RNA condensates whose assembly persists after several degradosome-client binding sites are removed. Eukaryotic P-bodies and stress granules are analogies, not exact identities.
CURATION_TODO (OPEN): Establish exact taxon-neutral family groundings for the RhlB and aconitase client classes. The verified strain-specific UniProt mappings identify the assayed loci, but domain and broad superfamily matches cannot substitute for exact whole-protein family groundings. Current UniProt calls CCNA_01923 RhpA, whereas the paper and gene symbol call it RhlB; this nomenclature difference is explicitly retained.
CURATION_TODO (RESOLVED): Distinguish the verified NA1000 example from species-wide prevalence. A species-level VARIABLE presence row would imply patchiness across lineages that the curated NA1000 experiments do not establish. A qualifying note cannot remove that assertion from the structured field.

Evidence

GO:0140365 Active GO cellular-component identity with exact BR-body synonym and original-paper PMID 30197298; GO:0036464 is its is-a parent.
DOI:10.1016/j.molcel.2018.08.003 Al-Husini et al. 2018, alpha-proteobacterial RNA degradosomes assemble liquid-liquid phase separated RNP bodies. Full-text results and methods read through NCBI PMC BioC (PMC6151146).
DOI:10.1016/j.molcel.2020.04.001 Al-Husini et al. 2020, BR-bodies provide selectively permeable condensates that stimulate mRNA decay and prevent release of decay intermediates. Results read through NCBI PMC BioC (PMC7245546).

Curation history

2026-10-03T11:59:25Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-10-03T12:00:58Z codex · EXPANDED_RECORD — Added GO identity and parentage, four evidence-backed components with verified NA1000 protein examples, scoped taxonomy and mRNA-decay function, a six-edge mechanistic graph, condensate boundaries and client-family follow-up.
2026-10-03T12:03:07Z codex · TIGHTENED_TAXONOMY_SCOPE — Removed provisional species prevalence assertion; retain experimentally demonstrated NA1000 as a canonical example without inferring lineage patchiness.

Source: data/structures/ribonucleoprotein/rnp_body.yaml