ASpks MTB000057
ncRNA Putative small regulatory RNA
This is an RNA, not a coding gene: it belongs to a separate track and carries none of the protein evidence layers.
Location
2299745–2299886 (+ strand), 142 nt, on H37Rv
(NC_000962.3).
Overlaps: Rv2048c.
Upstream neighbour Rv2047c
(5219 bp).
Downstream neighbour Rv2049c
(7407 bp).
Intra-MTBC variation
| Genomes surveyed | 145,209 |
| Variable sites | 1 |
| Variants reaching 0.1 % of genomes | 0 |
| Carriers of the most widespread variant | 1 |
Coverage control
Variant density inside this RNA: 0.7 sites/100 bp, versus 20.1 in the flanking ±500 bp (GC 63.4 %). The flanks act as an internal witness: if variants are called normally around the RNA but none becomes widespread inside it, the constraint is real rather than a sequencing gap.
Verdict: SUSPECT — voisinage appauvri (20 vs mediane 65/100 pb) : couverture regionale douteuse
Cause. Mycobrowser's own note on this entry gives the reason: 'This sequence is repeated in pks12|Rv2048c at position 2305814-2305955'. A repeated sequence does not receive reliable variant calls, so the apparent invariance (0.7 variant sites/100 bp inside vs 20.1 in the flanks) is a mapping artefact, not a constraint.
Read with care: constraint is not function. This RNA mutates like its surroundings, but no variant spreads through the population — which is evidence of selection acting on it, not evidence of what it does. Secondary-structure pairing was tested across the RNA set and did not explain this constraint.
Predicted secondary structure
49.3 % of bases are paired in the minimum-free-energy fold (70 paired, 72 unpaired). Folded in isolation; the in vivo structure may differ (partners, co-transcriptional folding).
Literature cited
ASpks was described as a putative sRNA antisense to pks12 (Arnvig & Young 2009) and appears in genome-wide sRNA expression surveys.
Read with care. Do NOT confuse it with ASpks2 (JBC 2026), an sRNA targeting pks2/Rv3825c: similar names, different loci. And this entry is excluded from the constrained candidates by its coverage verdict.
Sweep: tbmonitor TB corpus (~330k PubMed abstracts), name sweep of 2026-08-10; positive controls MTS2823 (6 papers), mcr11 (3), Mcr7 (2) all returned hits, so a zero here is a measured absence and not a broken query.
Legacy record
ASpks, putative small regulatory RNA (See Arnvig and Young, 2009). Alternate 5'-ends at positions 2299785 and 2299796. Alternate 3'-end at position 2299873. This sequence is repeated in pks12|Rv2048c at position 2305814-2305955.
Sources
- Descriptive record (locus, name, product, comment, coordinates): Mycobrowser v5, stable RNAs (Kapopoulou et al. 2011, doi:10.1016/j.tube.2010.09.006).
- Intra-MTBC variation and coverage control: computed for this atlas over 145,209 genomes.
- Secondary structure: ViennaRNA 2.7.2, MFE fold.