POU2AF1 (OCA-B / OBF-1 / BOB-1) - the B-cell-restricted OCT coactivator, in the Q152 AFF1-only core
also called OCA-B · OBF-1 · OBF1 · BOB-1 · BOB1 · OCT-binding factor 1
POU2AF1 makes a helper protein that only B cells have; it works with the OCT transcription factors to switch on B-cell genes. Its switch is occupied in half the KMT2A::AFF1 infant samples we looked at and in none of the others, but that pattern is common enough by chance that it is not on its own evidence of anything.
The same thing, for a scientist
POU2AF1 (Q16633, 256 aa) is the B-cell-specific transcriptional coactivator OCA-B/OBF-1/BOB-1, which has no DNA-binding domain of its own and works through POU2F1/POU2F2 at octamer motifs. It is one of two genes in the Q152 17-promoter AFF1-only core annotated to GO:0030183 B cell differentiation, and one of the three that give the core its lymphoid appearance. Its promoter is occupied in 4 of 8 KMT2A::AFF1 samples of GSE252378 (TB051939, TB920488, TB986292, p247) at 2.06-7.04x, with the highest non-AFF1 value 1.91x - a separation margin of 1.08, one of the narrowest in the core.
Why the 7.04x does not mean what it looks like
POU2AF1 carries the single strongest occupied call in the whole 17-gene core, 7.04x in one sample. Its weakest occupied call is 2.06x and its best non-AFF1 sample is 1.91x, so its margin is 1.08 - joint third narrowest. Quoting the 7.04x alone would repeat the error this project has made before of publishing a set's best value as its range 2.
What is genuinely notable
The four occupied samples are TB051939, TB920488, TB986292 and p247 - and the first three are the three TB-prefixed AFF1 samples, i.e. the occupancy is concentrated in one sub-block of the arm rather than spread across it. That is a batch-shaped pattern and is recorded as such; this beat did not test for a batch effect.
| uniprot | Q16633 |
|---|---|
| length AA | 256 |
| gene symbol | POU2AF1 |
| hgnc symbol | POU2AF1 |
| chromosome | 11q23.1 |
| promoter hg38 | chr11:111,378,275-111,380,275 (TSS 111,379,275, minus strand, NM_006235) |
| shown for fusion | NO - nobody has published a KMT2A-fusion occupancy or knockdown experiment on POU2AF1 that this beat could find; a PubMed search for (POU2AF1 OR BLNK OR TBX21 OR SPRED1 OR EPHA7)[tiab] AND (KMT2A OR MLL)[tiab] returned 5 records, none of them about POU2AF1. |
| relationship to existing entries | Named by beat Q152 because its promoter sits in the 17-gene AFF1-only recurrent core of GSE252378. Q152's headline result is that that core is NOT more recurrence than a label permutation gives (p = 0.11), and the apparent lymphoid character of the core does not survive an activity-matched null (p = 0.105 and 0.043 against a 0.025 threshold). This entry therefore does NOT claim the gene is a KMT2A::AFF1 target. It exists because the gene is real biology in this disease and had no entry. |
measurements
[
{
"quantity": "n_aff1_samples_occupied",
"subject": "POU2AF1 2 kb promoter in the KMT2A::AFF1 arm of GSE252378",
"value": 4,
"units": "samples of 8",
"n": 27,
"universe": "27 GSE252378 KMT2A-fusion samples, two-antibody 2.0x within-sample share plus per-library width-matched floor",
"null": 2.73,
"note": "TB051939, TB920488, TB986292, p247; occupied calls 2.06-7.04x; 0 of 19 non-AFF1, highest non-AFF1 1.91x (p160), separation margin 1.08. Null 2.73 is q151's per-promoter expectation across 27 samples; Q152's permutation null shows this pattern is within the chance range. The 7.04x is a single sample's value; the set's weakest occupied call is 2.06x."
}
]- The POU2AF1 TSS (chr11:111,379,275) is 7.06 Mb from the KMT2A TSS (chr11:118,436,491) on the same chromosome arm. Is its promoter occupancy a proximity artefact of a rearranged chromosome 11 rather than a trans-acting fusion event? Copy-number and breakpoint position were not checked in this beat and this is the cheapest remaining test on this gene.
- Is the concentration of occupancy in the three TB-prefixed libraries a batch effect?
- E1established confidence 5 of 5: Multiple independent lines of evidence; treated as settled in the field.database
POU2AF1 is a reviewed human UniProt entry, accession Q16633, 256 residues, POU domain class 2-associating factor 1, also known as B-cell-specific coactivator OBF-1, BOB-1 and OCA-B.
UniProtKB Q16633 - POU domain class 2-associating factor 1 (Homo sapiens), reviewed · UniProt Consortium · UniProtKB/Swiss-Prot 2026What this evidence cannot show
gene_exact:POU2AF1 returns one reviewed human record. BOB1 is a contaminated search token - it also names a plant and fungal gene and an unrelated protein in other organisms - so literature searches on POU2AF1 should use the official symbol first. No row exists in data/symbol-collisions.json (checked, 211 rows); one could reasonably be added.
Evidence that argues against this (1)
- BOB1 and OBF1 are used as symbols for unrelated genes in plants and fungi, so any literature count on those aliases is contaminated; the 324-record count this beat obtained for POU2AF1 OR OBF1 OR BOB1 is an upper bound, not a measure of the human literature. UniProt Consortium 2026
- E2moderate confidence 3 of 5: One strong study, or several smaller consistent ones.dataset
In GSE252378 the POU2AF1 2 kb promoter (hg38 chr11:111,378,275-111,380,275, minus-strand refGene TSS 111,379,275, NM_006235) is occupied in 4 of 8 KMT2A::AFF1 samples (TB051939, TB920488, TB986292, p247) at min-of-replicate within-sample shares of 2.06-7.04x and in 0 of 19 non-AFF1 samples, with the highest non-AFF1 value 1.91x in p160 - a separation margin of 1.08.
Q152 per-core-gene occupancy and separation margins over GSE252378 · Iqbal Lab oncofusion knowledge graph, beat Q152 · this project 2026What this evidence cannot show
Q152's own label-permutation null shows a 4-of-8 AFF1-exclusive pattern is within the chance range for this rule, so this is an observation, not a target call. Three of the four occupied samples are the three TB-prefixed AFF1 libraries, which is a batch-shaped pattern that was not tested for.
Evidence that argues against this (1)
- Three of the four occupied samples are the three TB-prefixed libraries, which is consistent with a batch or processing effect rather than biology; no batch covariate was available or tested. NCBI Gene Expression Omnibus 2024
- E3established confidence 5 of 5: Multiple independent lines of evidence; treated as settled in the field.database
POU2AF1 is annotated to GO:0030183 B cell differentiation (human, including descendant terms), one of 115 human protein symbols so annotated and one of 62 that are in the 6,049-promoter occupied-anywhere universe of GSE252378.
QuickGO annotation service - human protein annotations to GO:0030183 (B cell differentiation) and GO:0030098 (lymphocyte differentiation), including descendant terms · EMBL-EBI Gene Ontology Annotation · EMBL-EBI 2026What this evidence cannot show
GO annotation sets change between releases and the QuickGO search endpoint returns no release identifier; fetched 2026-09-24.
Evidence that argues against this (1)
- GO:0030183 membership is a curated annotation, not a measurement in this disease. POU2AF1's B-cell role is established in normal development and its behaviour in an infant KMT2A::AFF1 blast, which is arrested at a pro-B-like stage, is not the same question. EMBL-EBI Gene Ontology Annotation 2026
one of the two GO:0030183 members of the core
named by this beat; carries the core's single strongest call at 7.04x and one of its narrowest margins at 1.08
B-cell-restricted OCT coactivator; the index disease is infant B-ALL