Rv0229c Family assigned · medium

H37Rv Rv0229c · MTBC0 mtbc0_000243 · 137 aa · 274687–275100 MTBC0 (-) · RefSeq NP_214743.2

Genomic neighbourhood (genome browser)

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Annotation: from legacy to revised

Legacy (H37Rv / Mycobrowser)hypothetical protein
MTBC0 PGAP re-annotationPIN domain nuclease
Revised (this work)PIN-domain ribonuclease, VapC-family toxin (Pfam PIN PF01850): the toxin of a VapBC-type toxin-antitoxin module, a metal-dependent mRNA interferase that cleaves RNA.
Functional category (TubercuList)cell wall and cell processes

In the literature (TB corpus sweep) 1 publication

Found under: H37Rv (1).

1 TB publication mentions this gene. 1 publication(s) mention this gene (title/abstract), verified against the text. The atlas states the function; these are the primary sources that discuss it.

PublicationDate
Mycobacterium tuberculosis Rv0229c Shows Ribonuclease Activity and Reveals Its Corresponding Role as Toxin VapC51. doi:10.3390/antibiotics12050840 2023

This layer CITES the literature, it does not change the verdict or the function. A gene may be heavily studied (as an antigen, a resistance determinant, a drug target) while its molecular function is settled elsewhere in the fiche. This distinguishes a gene that is dark because nobody has looked from one that is dark despite having been studied. Source: PubMed (whole), MULTI-ALIAS sweep: H37Rv locus tag AND every ortholog identifier (M. bovis Mb…, M. marinum MMAR_…, M. smegmatis MSMEG_…, M. leprae ML…, M. abscessus MAB_…), each hit VERIFIED against the abstract text (word-boundary regex). phase73/phase75, 2026-07-13.

Genomic-neighbour overlap (structural caveat) co-directional · 1 % of gene

Neighbourphp (Rv0230c, - strand)
Overlap4 bp, 1 % of this gene's length

co-directional overlap: ordinary (e.g. shared stop/start codons in an operon), not the Rv2438A-type artefact P20.1, derived from GFF3 gene coordinates, 2026-08-03.

CRISPRi vulnerability

Vulnerability index -0.20 (95% CI -2.00 to 2.24). A more negative index = more vulnerable to knockdown (better drug-target quality); indicative threshold VI ≤ -6 = highly vulnerable.

Quantitative CRISPRi knockdown, graded (finer than binary Tn-seq essentiality). Source: CRISPRi vulnerability index (Bosch 2021, pebble.rockefeller.edu).

Orthologues (reciprocal best hits across mycobacteria)

M. bovis Mb0234c · 99.6% identity
M. orygis RJtmp_000243 · 100.0% identity

Reciprocal-best-hit orthologues (DIAMOND) against the Mycobrowser reference proteomes. A missing species is informative: e.g. a gene absent from M. leprae was likely lost in its reductive genome evolution. Locus tags link to Mycobrowser.

Curated reference (UniProt)

UniProt L0T5V6 SwissProt · reviewed · Evidence at protein level
UniProt nameRibonuclease VapC51
EC (curated) EC 3.1.-.-
Curated functionToxic component of a type II toxin-antitoxin (TA) system. An RNase. Its cognate antitoxin is VapB51.

Functional vocabulary (eggNOG-mapper, orthology transfer)

COG category S Function unknown
eggNOG descriptiontoxic component of a
Orthologous groupCOG1487

Orthology-based transfer (eggNOG 5.0.2, diamond). EC/KO/GO/CAZy are computed annotations, not manual curation; cross-check against the primary literature before treating a specific reaction as established.

Conservation & selection (intra-MTBC, 145 209 strains)

pN/pS 1.371 · diversifying/relaxed
Polymorphic sites (≥ 0.1% of strains) 1 synonymous, 4 missense, 0 nonsense, 0 frameshift

pN/pS from segregating SNPs (singletons removed) normalised by possible sites. Low pN/pS = purifying selection (a strong signal that a "hypothetical" is a real, constrained gene). A high pN/pS is ambiguous: relaxed constraint or positive selection (drug resistance, antigenic variation) inflate it; e.g. rpoB/katG/pncA score high here for resistance, not loss of function. A clonal disruption (one allele over a clade) suggests lineage pseudogenisation; a convergent one (many independent alleles) is typical of resistance loss-of-function.

Outgroup conservation (beyond the MTBC) Mycobacterium

M. canettii dN/dS (deep-divergence selection) 0.0 (low power) · 1 consensus substitution(s)
low power (1 canettii-consensus substitution(s)); present in M. canettii but dN/dS not reliable
Genus-wide presence (~53 non-MTBC Mycobacterium) present in 19/53 (36%) · mean identity 48.0% · 3/4 closest MTBAP relatives
present in a subset of the genus (19/53 NTM; in 3 of the 4 closest MTBAP relatives) — partial/intermediate conservation
Phylostratum (deepest detected homolog) MTBC-specific Mycobacterium Mycobacteriaceae Corynebacteriales Actinomycetia Bacteria

present across the genus Mycobacterium (NTM) but not detected in any non-Mycobacterium genome — a Mycobacterium-genus gene

Two orthogonal outgroup signals. M. canettii (the immediate outgroup) gives a deep-divergence dN/dS (a low value confirms a constrained, real gene; shown as confident only at ≥8 substitutions, else flagged low-power). Genus-wide presence/absence (tblastn vs assembled non-MTBC genomes) places the gene on the ancient-core ↔ MTBC-specific axis: a gene absent even from the closest MTBAP relatives is a candidate MTBC-specific innovation (possible host-adaptation factor, to confirm by synteny). The phylostratum extends that axis outside the genus (tblastn vs 13 reference genomes spanning Mycobacteriaceae → Corynebacteriales → Actinomycetia → outside the phylum): it is the deepest clade in which a homolog is still detected, i.e. a proxy for gene age. Read it with the null model in mind: a shallow (young) stratum can also reflect homology-detection failure for short or fast-evolving ORFs, so it is a descriptive axis, not a proof of novelty.

Essentiality (transposon mutagenesis)

DeJesus 2017 callNE · non-essential
What the call meansnon-essential
TA sites (Himar1) 17 in the ORF — 0 in the essential state, 0 growth-defect, 17 non-essential, 0 growth-advantage. Saturation 1.000, mean read count 115.058823529. A region of the protein devoid of TA sites is invisible to this assay: nothing can be inferred about it, in either direction.

Genome-wide Himar1 transposon essentiality in H37Rv (DeJesus 2017). An essential call (ES/ESD/GD) is strong, independent evidence that a "hypothetical" locus encodes a functional, selectively required gene — orthogonal to intra-species conservation.

Proteomics (mass spectrometry) detected

MS detectiondetected in 12 of 16 independent MS datasets
Integrated abundance105.0 ppm · rank 1269/3519 (64.0th percentile)

Detection by mass spectrometry is direct, experimental evidence that the protein product exists — orthogonal to sequence conservation and to Tn-seq essentiality, and especially decisive for a "hypothetical" locus. Reproducible detection across several independent datasets (PaxDb) makes the existence claim robust; the integrated abundance places the protein in the proteome's dynamic range.

Physico-chemical properties (computed, ProtParam)

Length137 aa
Molecular weight15.0 kDa
Theoretical pI6.91
GRAVY0.043 (hydrophobic)
Aliphatic index110.5
Aromaticity0.051
Instability index37.0 (stable)

Computed from the ancestral MTBC0 sequence with the ExPASy ProtParam method (Biopython). Descriptive biophysical context: a positive GRAVY flags a hydrophobic (often membrane) protein, a high instability index (>40) predicts a short in-vitro half-life, an extreme pI hints at compartment or binding partner.

Domains (Pfam, hmmscan --cut_ga)

PfamAccessioni-EvalueResiduesDescription
PINPF01850.28 6.6e-115–120 PIN domain

Structural search (AlphaFold DB model, Foldseek vs PDB — genome-wide) pLDDT 96.3

PDB hitprobTM-scoreE-valueDescription
5sv2-assembly1_A-2 1.00 0.90 8.8e-13 sig 5sv2-assembly1_A-2 Toxin VapC21 from Mycobacterium tuberculosis
3h87-assembly1_B 1.00 0.88 6.5e-11 sig 3h87-assembly1_B Rv0301 Rv0300 Toxin Antitoxin Complex from Mycobacterium tuberculosis
6a7v-assembly1_E 1.00 0.82 2.9e-09 sig 6a7v-assembly1_E Crystal structure of Mycobacterium tuberculosis VapBC11 toxin-antitoxin complex
4chg-assembly3_E 1.00 0.88 1.9e-07 sig 4chg-assembly3_E Crystal structure of VapBC15 complex from Mycobacterium tuberculosis
5ecw-assembly1_A 1.00 0.82 2.2e-07 sig 5ecw-assembly1_A Structure of the Shigella flexneri VapC mutant D7A

Foldseek search of the AlphaFold DB model (mean pLDDT 96.3, gated at 70) against the PDB — a genome-wide extension of the ESMFold dark-gene search that also covers proteins beyond the single-sequence length limit. Confident structural neighbours (E < 0.01) shown.

Genomic context (neighbours & predicted operon) operon of 2

Upstream (5' on genome)Rv0228 (+ strand, 27 bp gap)
Downstream (3' on genome)php (- strand, -4 bp gap)
Predicted operon Rv0229c · php

Neighbours from the H37Rv annotation (- strand). The operon is predicted by co-directional intergenic distance (same strand, gaps ≤50 bp) — a transcription-unit hypothesis, not a mapped TSS. For a "hypothetical", co-transcription with a characterised operon is a concrete functional lead (complements the STRING neighborhood channel below).

Transcriptional regulation (signed TRN: ChIP-seq + TFOE)

Regulated by (3 TF) Rv0047c (represses) · whiA (activates) · lsr2 (represses)

Regulatory edges from the ISB signed transcriptional regulatory network (TF ChIP-seq binding, Minch 2015 + TF-overexpression response, Rustad 2014). An edge is regulatory evidence (binding and/or expression change), not necessarily direct. For a "hypothetical", membership in a known regulon (e.g. DosR dormancy, PhoP virulence) is a strong physiological-context lead.

Functional interaction network (STRING v12, guilt-by-association)

Explore full network →

Node colour = verdict, dashed = hypothetical; edge colour = evidence (green experimental, orange genomic-context, grey co-expression), width ∝ score. Click a partner to open its page; "Explore full network" to walk the graph.

Closest characterised functional partner: php (phosphotriesterase), high confidence from genomic context alone (score 799 excluding text-mining). This association is the citable seed of a function hypothesis for this hypothetical protein.

PartnerProductScoreNo text-miningChannels (≥400)
Rv0230c php phosphotriesterase 902 799 ctx neighborhood:799 textmining:532
Rv0231 fadE4 acyl-CoA dehydrogenase FadE4 562 562 ctx neighborhood:562
Rv0582 vapC26 ribonuclease VapC26 483 483 ctx cooccurence:474
Rv0300 vapB2 exp antitoxin VapB2 444 445 experimental:412
Rv1607 chaA ionic transporter integral membrane protein ChaA 440 440 ctx cooccurence:439
Rv2601A vapB41 antitoxin VapB41 434 412
Rv1952 vapB14 antitoxin VapB14 429 407
Rv0595c vapC4 ribonuclease VapC4 440 265
Rv0268c hyp hypothetical protein 470 69 textmining:454
Rv0366c hyp hypothetical protein 731 62 textmining:726
Rv0207c hyp hypothetical protein 803 55 textmining:801
Rv3662c hyp hypothetical protein 515 52 textmining:510
Rv3641c fic cell filamentation protein Fic 871 50 textmining:870
Rv0078A hyp hypothetical protein 804 50 textmining:803
Rv2165c rsmH rRNA small subunit methyltransferase H 804 47 textmining:803

STRING combines evidence channels (neighborhood, fusion, cooccurrence, coexpression, experimental, database, text-mining) into a 0–1000 score. The ctx badge marks edges carried by the genomic-context channels (conserved neighborhood, fusion, phylogenetic co-occurrence), which are independent of orthology and structure and the strongest signal for an unknown gene. The exp badge marks an experimentally-supported partner (measured interaction, experimental/database channel ≥400) as opposed to a purely predicted one — but note that the M. tuberculosis experimental interactome is dominated by a noisy bacterial-two-hybrid screen, so a strong measured link that contradicts the operon/localisation context is likely a false positive. The no text-mining column recomputes the score from data alone, so a link that does not depend on the literature is visible. Association is a function hypothesis, not proof: corroborate with the operon context and the primary literature before assigning a function.

Evidence

  • MTBC0 PGAP product: 'PIN domain nuclease'
  • Pfam: PIN PF01850 (E=6.6e-11) -- VapC-type metal-dependent RNase

ESM Atlas signal (exploratory)

Ancestral protein hash a578a5f3c4bce26c8788866c3281b74f · 10 ESM-space neighbours (max similarity 0.924). SAE features are orienting indices, not validated domains.

#IndexActivationInterpretation
112085 1.20 Acidic N-terminal nuclease motif
2304 1.06 PIN/NYN endoribonuclease catalytic core
36726 1.06 Divalent-metal active-site loops
415824 1.02 VapC PINc RNase scaffold
5765 1.01 Acidic PIN/NYN endonuclease regions
65964 0.87 Metallo-phosphoesterase active-site entry
715408 0.86 Acidic phosphate-binding catalytic helix
815033 0.79 Acidic metal-binding nuclease active site

Sources

  • Ancestral sequence & coordinates: Harrison LB et al. (2024), An imputed ancestral reference genome for the MTBC, doi:10.1101/2023.09.07.556366
  • Product annotation: NCBI PGAP on MTBC0; legacy from H37Rv NC_000962.3 (RefSeq NP_214743.2)
  • Domains: Pfam-A via hmmscan --cut_ga — PIN (PF01850.28)
  • Sequence-level signal: ESM Atlas (EvolutionaryScale × BioHub) — exploratory
  • Controlled vocabulary: eggNOG-mapper 2.1.12 (Cantalapiedra et al. 2021, doi:10.1093/molbev/msab293), eggNOG 5.0 DB (Huerta-Cepas et al. 2019) — OG COG1487
  • Curated reference: UniProt L0T5V6 (SwissProt, reviewed; Evidence at protein level)
  • Intra-MTBC selection: pN/pS and disruption from SPDI variants of 145 209 MTBC strains (this work, local collection vs H37Rv NC_000962.3)
  • Genome-wide structure: AlphaFold DB model (Jumper et al. 2021, doi:10.1038/s41586-021-03819-2; Varadi et al. 2024, doi:10.1093/nar/gkad1011) searched vs PDB with Foldseek (mean pLDDT 96.3)
  • Interaction network: STRING v12.0 (Szklarczyk et al. 2023, doi:10.1093/nar/gkac1000), taxon 83332, CC-BY 4.0 — 20 functional partner(s); context anchor php
  • Essentiality: genome-wide transposon mutagenesis in H37Rv — DeJesus et al. 2017 (mBio, doi:10.1128/mBio.02133-16, CC BY)
  • Proteomics: integrated mass-spectrometry abundance from PaxDb 5.0 (Huang et al. 2023, doi:10.1016/j.mcpro.2023.100640), taxon 83332 — weighted average of 16 datasets, incl. Schubert et al. 2013 (doi:10.1016/j.chom.2013.04.008) and Albrethsen et al. 2013 (doi:10.1074/mcp.M112.018846)
  • Functional category: TubercuList scheme (Cole et al. 1998, doi:10.1038/31159), via Mycobrowser (Kapopoulou et al. 2011, doi:10.1016/j.tube.2010.09.006)
  • Orthologues: reciprocal best hits (DIAMOND, Buchfink et al. 2021, doi:10.1038/s41592-021-01101-x) against Mycobrowser release 5 reference proteomes
  • Genomic context / operon: H37Rv annotation; operon predicted by co-directional intergenic distance (Salgado et al. 2000, doi:10.1073/pnas.030539397)
  • Transcriptional regulation: ISB signed TRN — TF ChIP-seq (Minch et al. 2015, doi:10.1038/ncomms6829) + TF overexpression (Rustad et al. 2014, doi:10.1186/gb-2014-15-11-502)
  • Physico-chemical properties: ExPASy ProtParam method via Biopython (Gasteiger et al. 2005), computed from the MTBC0 sequence
  • Primary literature: none located yet; annotation rests on the domain/homology sources above.

Ancestral MTBC0 protein sequence

>mtbc0_000243|Rv0229c|
MALKYLLDTSVIKRLSRPAVRRAVEPLAEAGAVARTQITDLEVGYSARNETEWQRLMVALSAFDLIESTASHHRRALGIQRLLAARSQRGRKIPDLLIAAAGEEHGLVVLHYDADFDLIAAVTGQPCQWIVPAGTID