guca1c notes (Danio rerio, guanylate cyclase activator 1C, zGCAP3; UniProt Q8UUX9)

2026-09-28 — session log (DANRE_DUPLICATION batch 4, random TGD_tree sample)

Deep research: not available (Edison 402 Payment Required; OpenAI key invalid). Not attempted, per
instructions. Literature found by hand through Europe PMC; pair analysis in
guca1c-bioinformatics/RESULTS.md.

Accession Q8UUX9 (TrEMBL, 188 aa), ZFIN:ZDB-GENE-030829-1, Ensembl ENSDARG00000030758, chr15. Paralog guca1d
(zGCAP4, chr21). PANTHER TGD_tree pair (PTHR23055, GUCA1C co-orthologs); Ensembl Compara places the
guca1c/guca1d duplication at Osteoglossocephalai, with one gar ortholog (ENSLOCG00000009269, LG3) for both.

Name mapping (checked against ZFIN aliases.txt, see RESULTS.md section 0)

• gcap1 = guca1aa (formerly guca1a); gcap2 = guca1b; gcap3 = guca1c; gcap4 = guca1d;
  gcap5 = guca1ab.1 (formerly guca1e); gcap7 = guca1g. guca1ab.2 (formerly guca1e.2) has no GCAP number.
• Lamb & Hunt call zGCAP3/zGCAP4 "GCAP3a/GCAP3b":
  PMID:30257895
• Morales-Camara: PMID:32422965

Expression

• All cone types, not rods: PMID:11860507
• Onset 3-4 dpf: PMID:19168097
• Protein: PMID:22212098
• Molar excess over zGC3: PMID:23940527
• My reanalysis of adult photoreceptor scRNA-seq (GSE175929, PMID:34462505): guca1c in 100% of cones of every
  type, 57-75 CP10K, about ten times guca1d; rod signal is at the ambient level of gnat2
  (guca1c-bioinformatics/scrna_output.txt).
• E-ERAD-475 whole embryo: guca1c 3 TPM, guca1d 5-8 TPM at 3-5 dpf (larval retina is a small fraction of the body).

Function

• Ca2+-dependent GC activation: PMID:11860507
• High Ca2+ sensitivity group: PMID:21829700
• Native membranes: PMID:23940527
• Morpholino knockdown, no behavioural defect: PMID:23940527
  Authors propose zGCAP4 as substitute: PMID:23940527
• CRISPR knockout (NMD-type allele; mRNA below 40% of wild type):
  PMID:32422965
  Phenotype: PMID:32422965
  Caveats: anti-human GUCA1C antibody; the signals vanish in the knockout, PMID:32422965
  but the rod and ciliary-epithelium staining conflicts with cone-only transcript data; guca1d compensation not tested:
  PMID:32422965
  No GOA row derives from this paper; I did not propose NEW rows from it.

Annotation decisions

• Ca2+ binding (IBA, 3 IDA, IEA, ISS): ACCEPT.
• GO:0008048 (IBA, 4 IDA): ACCEPT (core). GO:0030250 ISS: ACCEPT (parent).
• GO:0009966 regulation of signal transduction (IBA, deep NCS node): KEEP_AS_NON_CORE.
• core_functions: GO:0008048; process GO:0031284 positive regulation of guanylate cyclase activity; location
  photoreceptor inner segment (antibody, abstract).