Rv0143c Resolved · high auto-curated

H37Rv Rv0143c · MTBC0 mtbc0_000154 · 492 aa · 169050–170528 MTBC0 (-) · RefSeq NP_214657.1

Genomic neighbourhood (genome browser)

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This gene (outlined) in its genomic context; arrows are neighbouring genes coloured by verdict. Click any gene to navigate. Pan and zoom in the full browser.

Annotation: from legacy to revised

Legacy (H37Rv / Mycobrowser)transmembrane protein
MTBC0 PGAP re-annotationchloride channel protein
Revised (this work)Chloride channel protein. Pfam: Voltage_CLC (PF00654.26).
Functional category (TubercuList)cell wall and cell processes

Auto-curated: this verdict and function were generated by rules from PGAP + Pfam + Foldseek and have not been hand-reviewed.

In the literature (TB corpus sweep) never studied

No publication mentions this gene in its title or abstract — not under its H37Rv locus tag, not under its gene name, and not under any ortholog identifier. Its annotation rests on sequence/structure evidence, with no primary study behind it.

This layer CITES the literature and adds context; it does not change the verdict or the function stated elsewhere in this fiche. This distinguishes a gene that is dark because nobody has looked from one that is dark despite having been studied. Source: PubMed (whole): H37Rv locus tag + GENE NAME + ortholog identifiers (Mb…, MMAR_…, MSMEG_…, ML…, MAB_…), under a mycobacterial context filter; hits verified against the abstract text. Species-context counts distinguish M. tuberculosis literature from literature on other mycobacteria. phase76/phase77, 2026-07-13.

CRISPRi vulnerability

Vulnerability index 1.22 (95% CI -0.65 to 4.32). 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).

Legacy record & comparison (Mycobrowser)

Mycobrowser functionUnknown; possibly ion channel involved in transport of chloride across the membrane.

The legacy Mycobrowser record is shown for verification. Mycobrowser is no longer maintained; its EC numbers predate recent nomenclature revisions, so a class change usually reflects re-numbering, not a conflict.

Orthologues (reciprocal best hits across mycobacteria)

M. bovis Mb0148c · 99.8% identity
M. marinum MMAR_0353 · 87.9% identity
M. smegmatis MSMEG_6465 · 67.3% identity
M. orygis RJtmp_000154 · 99.8% 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 P96820 TrEMBL · unreviewed · Evidence at protein level
UniProt nameProbable conserved transmembrane protein

Functional vocabulary (eggNOG-mapper, orthology transfer)

COG category P Inorganic ion transport and metabolism
Preferred nameclcA
eggNOG descriptionChloride channel
Orthologous groupCOG0038
KEGG orthology K03281

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 0.487 · purifying
Polymorphic sites (≥ 0.1% of strains) 7 synonymous, 8 missense, 1 nonsense, 2 frameshift
Disruption 3 distinct premature-stop/frameshift site(s); most common in 0.73% of strains (1056) · clonal

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) Actinomycetia

M. canettii dN/dS (deep-divergence selection) 0.0 (low power) · 2 consensus substitution(s)
low power (2 canettii-consensus substitution(s)); present in M. canettii but dN/dS not reliable
Genus-wide presence (~53 non-MTBC Mycobacterium) present in 34/53 (64%) · mean identity 83.4% · 4/4 closest MTBAP relatives
conserved across the genus (present in 34/53 non-MTBC Mycobacterium genomes, incl. distant relatives) — an ancient core gene predating the genus radiation
Phylostratum (deepest detected homolog) MTBC-specific Mycobacterium Mycobacteriaceae Corynebacteriales Actinomycetia Bacteria
detected in 3/13 non-Mycobacterium reference genomes (down to Actinomycetia) · mean identity 48.0%
detected across the class Actinomycetia (beyond Corynebacteriales) but not outside the phylum — an Actinobacteria-level ancient 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) 28 in the ORF — 0 in the essential state, 0 growth-defect, 28 non-essential, 0 growth-advantage. Saturation 1.000, mean read count 136.5. 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 10 of 16 independent MS datasets
Integrated abundance10.1 ppm · rank 2679/3519 (23.9th 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.

Predicted localisation (DeepTMHMM + lipobox)

Predictionpredicted membrane protein (10 TM helixes)
DeepTMHMM classTM
TM helices (DeepTMHMM)10

Transmembrane topology and signal peptide from DeepTMHMM (deep-learning reference predictor); lipoproteins from a (myco)bacterial lipobox motif. A sequence-based prediction of subcellular context.

Physico-chemical properties (computed, ProtParam)

Length492 aa
Molecular weight50.8 kDa
Theoretical pI7.79
GRAVY0.574 (hydrophobic)
Aliphatic index110.9
Aromaticity0.089
Instability index23.1 (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
Voltage_CLCPF00654.26 3.0e-85113–460 Voltage gated chloride channel

Structural search (AlphaFold DB model, Foldseek vs PDB — genome-wide) pLDDT 91.4

PDB hitprobTM-scoreE-valueDescription
7n9w-assembly1_B 1.00 0.81 9.4e-17 sig 7n9w-assembly1_B CLC-ec1 pH 4.5 100mM Cl Twist1
8gah-assembly1_A 1.00 0.81 2.9e-16 sig 8gah-assembly1_A CLC-ec1 L25C/A450C/C85A at pH 4.5 100mM Cl Twist
2htk-assembly1_B 1.00 0.82 1.1e-15 sig 2htk-assembly1_B Structure of the Escherichia coli ClC chloride channel Y445A mutant and Fab complex
7rsb-assembly1_B 1.00 0.81 6.6e-16 sig 7rsb-assembly1_B CLC-ec1 at pH 4.5 100 mM NaGluconate Turn
6v2j-assembly1_A-2 1.00 0.82 1.3e-15 sig 6v2j-assembly1_A-2 Crystal structure of ClC-ec1 triple mutant (E113Q, E148Q, E203Q)

Foldseek search of the AlphaFold DB model (mean pLDDT 91.4, 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)

Upstream (5' on genome)Rv0142 (+ strand, 66 bp gap)
Downstream (3' on genome)Rv0144 (+ strand, 101 bp gap)

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).

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: Rv0144 (transcriptional regulator), medium confidence from genomic context alone (score 559 excluding text-mining).

PartnerProductScoreNo text-miningChannels (≥400)
Rv0144 transcriptional regulator 560 559 ctx neighborhood:555
Rv1762c hyp hypothetical protein 452 452 ctx cooccurence:421
Rv2101 helZ helicase HelZ 470 438
Rv3432c gadB glutamate decarboxylase GadB 466 432
Rv0145 S-adenosylmethionine-dependent methyltransferase 417 418 ctx neighborhood:414
Rv0146 S-adenosylmethionine-dependent methyltransferase 415 415 ctx neighborhood:413
Rv3256c hyp hypothetical protein 436 409 coexpression:409
Rv1899c lppD lipoprotein LppD 403 403
Rv3907c pcnA poly(A) polymerase PcnA 414 47 textmining:411

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

  • Legacy H37Rv annotation: transmembrane protein
  • MTBC0 PGAP product: chloride channel protein
  • Pfam (hmmscan --cut_ga): Voltage_CLC PF00654.26 (E=3e-85)
  • (auto-curated by rules from PGAP + Pfam + Foldseek; not hand-reviewed)

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_214657.1)
  • Domains: Pfam-A via hmmscan --cut_ga — Voltage_CLC (PF00654.26)
  • 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 COG0038
  • Curated reference: UniProt P96820 (TrEMBL, unreviewed; 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 91.4)
  • Interaction network: STRING v12.0 (Szklarczyk et al. 2023, doi:10.1093/nar/gkac1000), taxon 83332, CC-BY 4.0 — 9 functional partner(s); context anchor Rv0144
  • 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)
  • Physico-chemical properties: ExPASy ProtParam method via Biopython (Gasteiger et al. 2005), computed from the MTBC0 sequence
  • Predicted localisation: DeepTMHMM (Hallgren et al. 2022, doi:10.1101/2022.04.08.487609) for transmembrane topology and signal peptide
  • Primary literature: none located yet; annotation rests on the domain/homology sources above.

Ancestral MTBC0 protein sequence

>mtbc0_000154|Rv0143c|
MAPGDWSVFAWHAANLPTMPEAEDIGNEAAGGRFGVSIRSAGYLRKWFLLGITIGVIAGLGAVVFYLALKYTSEFLLGYLADYQIPTPVGEGGHRGSTGFARPWAIPLVTTGGAVLSALIVAKLAPEATGHGTDEAIESVHGDPRAIRGRAVLVKMVASALTIGSGGSGGREGPTAQISAGFCSLLTRRLNLSNEDGRTAVALGIGAGIGAIFAAPLGGAALGASIPYRDDFDYRNLLPGFIASGTAYAVLGAFLGFDPLFGYIDAEYRFEKAWPLLWFVVIGLIAAAVGYLYARVFHASVAITRRLPGGPVLKPAIGGLLVGLLGLPIPQILSSGYGWAQLAADRGTLLSIPLWIVIVLPIAKILATSLSIGTGGSGGLFGPGIVIGAFVGAAIWRLGELTELPGVPHEPGIFVVVAMMACFGSVSRAPLAVMIMVAEMTGSFSVVPGAIIAVGIAALLLSRTNVTIYETQRLNRQTAEAERGGSDRPTTA