The selected Q8IMZ2 sequence has 559 residues. Exact comparison with long Orb Q9VCN7 establishes an identical 552-residue C-terminal region containing the RNA-binding machinery. This supports broad functional transfer, while not proving identical N-terminal regulation. PMID:27791065(https://pubmed.ncbi.nlm.nih.gov/27791065/) directly compares Orb and Orb2 RNA-binding preferences; only Orb findings are transferred. PMID:15737929(https://pubmed.ncbi.nlm.nih.gov/15737929/) establishes Orb-dependent translation and localization. PMID:11809824(https://pubmed.ncbi.nlm.nih.gov/11809824/) full text directly assays Orb expression and mutant cysts despite its MEI-218 title. The 13 GOA rows are reviewed; broad binding annotations are specified, while developmental consequences remain noncore.
The selected frozen UniProt record is retained in orb-uniprot-source.json, with the complete original prediction metadata in orb-predictions-source.json. It maps the exact accession to this FlyBase gene; current sequence identity does not establish the historical predictor input. Gene-level experiments support conserved functions unless a relevant isoform difference is established. Falcon research was requested with perplexity-lite fallback alongside publication caching. Primary publications and sequence observations, rather than AI summaries or ARBA assertions, support the curated conclusions.
The wrapper timed out and its fallback reported insufficient quota, but the original Falcon job later produced a complete report. The report and primary sources were inspected; no duplicate provider submission was made. The report supports Orb-specific CPEB RNA binding and translational regulation, distinguishing Orb2. It does not establish differences among Q8IMZ2 isoforms; local sequence comparison supports retention of the RNA-binding machinery.
Identity: Q8IMZ2 (559 aa, unreviewed TrEMBL) is the shared product of orb transcripts C and E. It is an N-terminally truncated isoform of the gene; the UniProt gene-centric canonical product is Q9VCN7 (915 aa, isoform A/G; no Swiss-Prot entry exists for fly orb). The existing exact comparison (RESULTS.md) shows residues 8–559 identical to Q9VCN7 364–915, so the isoform keeps RRM1, RRM2 and the ZZ zinc-binding domain but lacks the N-terminal ~356 residues (low-complexity/regulatory region). Other gene products: Q8IMZ3 (913), E1JIU4 (617).
Evolutionary grounding: PANTHER PTHR12566:SF9 (CPEB1 subfamily), consistent with PMID:27791065. SF9 also contains vertebrate CPEB1 (human Q9BZB8, Xenopus Q91572) and worm cpb-3. The interpro/panther/PTHR12566 family review agrees with this placement. PAINT IBAs (node PTN000286163, whole CPEB family) are attached only to canonical Q9VCN7 (mRNA 3'-UTR binding, translation repressor activity GO:0000900, ribosome binding, negative regulation of cytoplasmic translation, cytoplasm, nucleus, neuron projection, synapse); none are on Q8IMZ2. Those are left to the canonical review.
Literature added (cached): PMID:10525352, PMID:12538512, PMID:18434412, plus PMID:30865627 on microtubule repolarization.
Changes vs the previous review:
- regulation of translation (IEA) ACCEPT -> MODIFY to positive regulation of translation (GO:0045727); fly evidence is activation by polyadenylation. Orb does part of the work (target recognition and recruitment of PAP/Wispy), so this is participation, not just necessity.
- translation regulator activity kept ACCEPT (not refined to activator activity), because the family includes repressor function and Orb acts via polyadenylation rather than directly on the ribosome.
- The cytoplasm IDA row cites a nanos paper whose abstract never mentions Orb; accepted per curator, with independent support from PMID:11809824 immunostaining.
- Quotes rebuilt from primary data; review TAS (PMID:11700288) kept as a reference but not used as support.
- Developmental rows (germ cell development, oocyte D/V and A/P axis specification, germ plasm oskar mRNA localization) remain KEEP_AS_NON_CORE: Orb acts on the determinant mRNAs directly, but these are developmental deployments of the core activity.
- Not added: cytosolic mRNA polyadenylation (GO:0180011) and P-body/cell cortex locations, which are FlyBase annotations on the canonical product; they belong to that review.
Next relative: the canonical product Q9VCN7 has no review in the repo (genes/DROME/orb is keyed to Q8IMZ2), so it should be reviewed as genes/DROME/orb__Q9VCN7. No modules reference orb/CPEB.