Rv2324 Family assigned · medium auto-curated

H37Rv Rv2324 · MTBC0 mtbc0_002472 · 148 aa · 2621083–2621529 MTBC0 (+) · RefSeq NP_216840.1

Genomic neighbourhood (genome browser)

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Annotation: from legacy to revised

Legacy (H37Rv / Mycobrowser)AsnC family transcriptional regulator
MTBC0 PGAP re-annotationLrp/AsnC family transcriptional regulator
Revised (this work)Lrp/AsnC family transcriptional regulator. Pfam: HTH_AsnC-type (PF13404.13), HTH_24 (PF13412.13), AsnC_trans_reg (PF01037.29).
Functional category (TubercuList)regulatory proteins

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) 2 publications

2 TB publications mention this gene. 2 publication(s) discuss this gene (2 in a M. tuberculosis context, 1 in other mycobacteria — M. smegmatis (1)).

PublicationDate
Mycobacterium tuberculosis Rv2324 is a multifunctional feast/famine regulatory protein involved in growth, DNA replication and damage control. doi:10.1016/j.ijbiomac.2023.126459 2023
Mycobacterium Lrp/AsnC family transcriptional factor modulates the arginase pathway as both a sensor and a transcriptional repressor. doi:10.1016/j.jgg.2021.06.018 2021

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 0.68 (95% CI -0.39 to 2.47). 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 functionInvolved in transcriptional mechanism.

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 Mycobrowser is no longer maintained; its EC numbers predate recent nomenclature revisions, so a class change usually reflects re-numbering, not a conflict.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 Mb2351 · 100.0% identity
M. marinum MMAR_3624 · 84.5% identity
M. smegmatis MSMEG_1415 · 81.4% identity
M. orygis RJtmp_002405 · 100.0% identity
M. abscessus MAB_3839c · 71.7% 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 P71888 SwissProt · reviewed · Evidence at protein level
UniProt nameHTH-type transcriptional regulator Rv2324
Curated functionTranscriptional regulator involved in growth, DNA replication and damage control. Plays a crucial role in regulating survival and growth of M.tuberculosis. Could function as a global regulator in both the latent/persistent and active phases of growth. Binds to its own promoter region and to promoters of multiple metabolic genes, such as serB2, lat, ald and roc operon. In vitro, interacts with intrinsically curved and non-curved DNA molecules, and with both supercoiled and linear DNA, with higher affinity for supercoiled DNA. Binds to DNA recombination, replication and repair intermediates.

Functional vocabulary (eggNOG-mapper, orthology transfer)

COG category K Transcription
eggNOG descriptiontranscriptional
Orthologous groupCOG1522

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 0.653 · relaxed/neutral
Polymorphic sites (≥ 0.1% of strains) 1 synonymous, 2 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) Actinomycetia

Genus-wide presence (~53 non-MTBC Mycobacterium) present in 51/53 (96%) · mean identity 73.2% · 4/4 closest MTBAP relatives
conserved across the genus (present in 51/53 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 7/13 non-Mycobacterium reference genomes (down to Actinomycetia) · mean identity 48.2%
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) 3 in the ORF — 0 in the essential state, 0 growth-defect, 3 non-essential, 0 growth-advantage. Saturation 1.000, mean read count 133. A region of the protein devoid of TA sites is invisible to this assay: nothing can be inferred about it, in either direction.
CaveatStatistically thin call: only 3 TA (Himar1) sites in the whole ORF (atlas median 13; genes under 300 nt typically have very few). A DeJesus 2017 call built on so few independent observations is less robust than the same call on a longer gene, in either direction. Cross-check against the CRISPRi vulnerability index (independent of TA-site density) and, if this gene overlaps a neighbour (see Genomic-neighbour overlap section below), verify how many of its TA sites actually fall inside its own ORF. (P20.3)

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 8 of 16 independent MS datasets
Integrated abundance14.9 ppm · rank 2495/3519 (29.1th 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)

Length148 aa
Molecular weight16.4 kDa
Theoretical pI5.65
GRAVY-0.095 (hydrophilic)
Aliphatic index100.2
Aromaticity0.041
Instability index41.0 (unstable)

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
HTH_AsnC-typePF13404.13 3.5e-154–44 AsnC-type helix-turn-helix domain
HTH_24PF13412.13 1.9e-144–51 Winged helix-turn-helix DNA-binding
AsnC_trans_regPF01037.29 4.0e-1768–147 Lrp/AsnC ligand binding domain

Structural search (AlphaFold DB model, Foldseek vs PDB — genome-wide) pLDDT 94.6

PDB hitprobTM-scoreE-valueDescription
2w25-assembly1_B 1.00 0.93 3.5e-14 sig 2w25-assembly1_B Crystal structure of Glu104Ala mutant
2ivm-assembly1_A 1.00 0.94 3.0e-13 sig 2ivm-assembly1_A Crystal structure of a transcriptional regulator
2qz8-assembly1_B-2 1.00 0.90 2.2e-13 sig 2qz8-assembly1_B-2 Crystal structure of Mycobacterium tuberculosis Leucine response regulatory protein (LrpA)
2vc1-assembly1_B 1.00 0.93 7.8e-13 sig 2vc1-assembly1_B Feast or famine regulatory protein (Rv3291c)from M. tuberculosis complexed with L-Methionine
2w29-assembly1_B 1.00 0.91 3.0e-13 sig 2w29-assembly1_B Gly102Thr mutant of Rv3291c

Foldseek search of the AlphaFold DB model (mean pLDDT 94.6, 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)Rv2323c (- strand, 64 bp gap)
Downstream (3' on genome)Rv2325c (- strand, 228 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).

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

Regulated by (1 TF) Rv3736 (activates)
Regulonthis transcription factor regulates 52 target gene(s)

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: Rv2319c (universal stress protein), medium confidence from genomic context alone (score 615 excluding text-mining).

PartnerProductScoreNo text-miningChannels (≥400)
Rv2323c hyp hypothetical protein 943 710 ctx neighborhood:618 textmining:813
Rv1725c hyp hypothetical protein 692 690 coexpression:690
Rv2621c transcriptional regulator 656 655 coexpression:655
Rv2319c universal stress protein 713 615 ctx neighborhood:613
Rv2320c rocE cationic amino acid transporter permease RocE 650 613 ctx neighborhood:606
Rv2322c rocD1 Rv2322c, (MTCY3G12.12), len: 221 aa. Probable rocD1,ornithine aminotransferase, highly similar to N-terminal region of other ornithine amino 597 594 ctx neighborhood:590
Rv2321c rocD2 Rv2321c, (MTCY3G12.13), len: 181 aa. Probable rocD2,ornithine aminotransferase, highly similar to C-terminal region of other ornithine amino 684 593 ctx neighborhood:590
Rv3291c lrpA transcriptional regulator LrpA 531 532 coexpression:415
Rv1985c lysG HTH-type transcriptional regulator 502 474 coexpression:474
Rv3183 higA3 transcriptional regulator 463 441 coexpression:441
Rv3167c TetR family transcriptional regulator 426 409 coexpression:409
Rv0339c iniR transcriptional regulator 425 404
Rv3736 AraC/XylS family transcriptional regulator 434 402
Rv3066 DeoR family transcriptional regulator 554 398
Rv0792c transcriptional regulator 414 386

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: AsnC family transcriptional regulator
  • MTBC0 PGAP product: Lrp/AsnC family transcriptional regulator
  • Pfam (hmmscan --cut_ga): HTH_AsnC-type PF13404.13 (E=4e-15), HTH_24 PF13412.13 (E=2e-14), AsnC_trans_reg PF01037.29 (E=4e-17)
  • (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_216840.1)
  • Domains: Pfam-A via hmmscan --cut_ga — HTH_AsnC-type (PF13404.13), HTH_24 (PF13412.13), AsnC_trans_reg (PF01037.29)
  • 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 COG1522
  • Curated reference: UniProt P71888 (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 94.6)
  • Interaction network: STRING v12.0 (Szklarczyk et al. 2023, doi:10.1093/nar/gkac1000), taxon 83332, CC-BY 4.0 — 26 functional partner(s); context anchor Rv2319c
  • 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_002472|Rv2324|
MDRLDDTDERILAELAEHARATFAEIGHKVSLSAPAVKRRVDRMLESGVIKGFTTVVDRNALGWNTEAYVQIFCHGRIAPDQLRAAWVNIPEVVSAATVTGTSDAILHVLAHDMRHLEAALERIRSSADVERSESTVVLSNLIDRMPP