CG45100 (Hdac3-5'utr, Dmel_Hdac3_uORF) is a predicted 38-residue peptide encoded by an upstream open reading frame in the 5-prime leader of Hdac3 transcripts. It has no similarity to histone deacetylases or to any characterized protein family. Its central segment (residues 12-30) is strongly hydrophobic and is predicted to form a single transmembrane helix, flanked by basic residues on the N-terminal side. The peptide sequence, including this hydrophobic segment, is conserved across Drosophilidae, which fits a translated product under selection. No homolog outside the Drosophilidae has been found. Translation of the ORF, accumulation of the peptide, its membrane localization, and any function, either as a peptide acting in trans or as a uORF regulating Hdac3 translation in cis, have not been tested.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0003674 molecular_function | ND GO_REF:0000015 | ACCEPT | Summary: No molecular activity is known for the 38-residue uORF peptide; ND is the correct state. Reason: Exact-identifier literature searches (all aliases, including the uORF and Hdac3-5'utr names) found no publication testing this peptide. The product has no domain, no PANTHER family and no characterized homolog. Its only Drosophilidae homologs (D. mauritiana to D. rubida) are uncharacterized. Nothing can be transferred by homology, and HDAC3 deacetylase activity cannot be transferred from the downstream ORF of the same transcript. Supporting Evidence: file:DROME/CG45100/CG45100-deep-research-falcon.md No exact-target publication was found under A0A0B4LGP2, AHN57173.1, FBgn0266539, CG45100, Dmel_CG45100, Dmel_Hdac3_uORF, or Hdac3-5′utr. file:DROME/CG45100/CG45100-bioinformatics/RESULTS-rereview.md No homolog outside Drosophilidae was found, and none of the homologs is experimentally |
| GO:0005575 cellular_component | ND GO_REF:0000015 | ACCEPT | Summary: No experimental localization exists. A membrane location is a sequence-based hypothesis only. Reason: Phobius predicts one transmembrane helix (residues 12-30), and this hydrophobic segment is conserved across Drosophilidae. This makes membrane insertion a reasonable hypothesis, but no study has shown that the peptide is produced and where it localizes. A predicted helix in an ORF whose translation has not been demonstrated is not enough to replace ND with a membrane term, so ND stays as the honest state. Supporting Evidence: file:DROME/CG45100/CG45100-deep-research-falcon.md No exact-target publication was found under A0A0B4LGP2, AHN57173.1, FBgn0266539, CG45100, Dmel_CG45100, Dmel_Hdac3_uORF, or Hdac3-5′utr. file:DROME/CG45100/CG45100-uniprot.txt FT TRANSMEM 12..30 FT /note="Helical" FT /evidence="ECO:0000256|SAM:Phobius" |
| GO:0008150 biological_process | ND GO_REF:0000015 | ACCEPT | Summary: No biological process is established for the peptide or for the uORF. Reason: No study has tested the peptide (trans) or the uORF's effect on Hdac3 translation (cis). Hdac3 processes cannot be assigned to a separate translation product. A cis-regulatory role would in any case belong to the RNA element, not to the peptide this accession describes. Supporting Evidence: file:DROME/CG45100/CG45100-deep-research-falcon.md No exact-target publication was found under A0A0B4LGP2, AHN57173.1, FBgn0266539, CG45100, Dmel_CG45100, Dmel_Hdac3_uORF, or Hdac3-5′utr. |
Loading supporting content…
Download this section (compressed HTML)Q: Is the CG45100 uORF translated in vivo, and does the 38-residue peptide accumulate as a stable product? Peptide-level conservation across Drosophilidae suggests selection on the encoded sequence.
Q: Does translation of the CG45100 uORF regulate translation of the downstream Hdac3 coding sequence in cis, separately from any activity of the peptide in trans?
Experiment: Knock in a minimal epitope tag at the endogenous CG45100 ORF, or run targeted mass spectrometry for its predicted tryptic peptides, to test whether the peptide is made and where it localizes (membrane fractionation and imaging).
Type: endogenous tagging and targeted proteomics
Experiment: Make CRISPR alleles that separate cis from trans effects: a start-codon mutation, a frameshift that keeps RNA composition, and synonymous recoding. In each, measure Hdac3 protein and mRNA levels and score phenotypes, with peptide-only rescue.
Type: genome editing and translation reporter assays
Loading supporting content…
Download this section (compressed HTML)Loading supporting content…
Download this section (compressed HTML)Loading supporting content…
Download this section (compressed HTML)Loading supporting content…
Download this section (compressed HTML)