Sct

Spatial tier: STRICT_EXCLUSIVE · Class: OTHER · Top region: SCO (Subcommissural organ) · Positive regions: 6/554

44.9Discovery Score
38.3Targetability Score
CEvidence grade C
What this means: Sct: predicted fine-region profile is strict-exclusive, with 6 positive regions out of 554 (limit 12); direct spatial validation is required.

Function in SCO: evidence, prediction, innovation

Gene function
Sct encodes secretin, a 27-residue secretin/glucagon/VIP-superfamily peptide from duodenal S cells that drives pancreatic and biliary bicarbonate and fluid secretion through the class-B GPCR SCTR and Gs-cAMP-PKA. It is also central, made in cerebellar Purkinje cells and hypothalamic neurons and released from the neurohypophysis.
Region function
The subcommissural organ is a secretory ependymal gland under the posterior commissure at the third-ventricle/aqueduct junction, releasing SCO-spondin into CSF to form Reissner's fibre and shaping aqueduct patency, CSF flow and axial morphogenesis.
Published in this region
inferred No region-specific literature found. Secretin facilitates cerebellar GABA transmission as a retrograde messenger (Yung et al. 2001; Wang et al. 2019), works with vasopressin as a neurohypophysial regulator of water homeostasis (Chu et al. 2009), and its receptor mRNA occurs in circumventricular tissue including OVLT, SCO unscored (Toth et al. 2013).
Predicted function
Prediction: SCO-made secretin would be an autocrine/paracrine CSF hormone raising cAMP via SCTR in SCO and adjacent ependyma, driving anion and fluid secretion and linking CSF output to vasopressin water balance. Sspo-CreER x Sct-flox deletion should reduce SCO-spondin and CSF secretion; intracerebroventricular secretin should enlarge ventricles.
Innovation
★★★★☆ 4/5 Brain secretin biology is confined to cerebellum, hypothalamus and neurohypophysis; the SCO as a secretin source is untested.
Tools
Sct-null and Sctr-null mice (Chu et al. 2009); Sspo-Cre/Sspo-CreER, Car3-Cre/Spdef-Cre (Zhang et al. 2024); secretin (ChiRhoStim); antagonist secretin(5-27); RNAscope Sct/Sctr probes.
References

Direct evidence located at the region

Sct Allen ISH at the CCF centroid of SCO

Allen ISH experiment 74357731, section image 74269951 (section 150): the section that contains the CCF centroid of Subcommissural organ according to the Allen image-to-atlas alignment (reference_to_image), with a 2 mm window around that point. Left: whole section, red box = window. Middle: ISH signal. Right: Allen's expression-mask view of the same window. open this image in the Allen viewer

Look it up yourself: Allen Mouse Brain ISH for SctAllen reference atlas: SCO (structure 599626923)ABC Atlas MERFISH viewer(in the ABC Atlas choose dataset MERFISH-C57BL6J-638850-CCF, colour cells by gene "Sct" or by parcellation_substructure "SCO")All genes confined to SCO + 3-D brain

Direct spatial evidence

MERFISH REGION LOCATOR
SCO MERFISH region locator
Real single-cell MERFISH coordinates for the SCO (Subcommissural organ) section -- our own ground-truth data, showing exactly where this region sits, independent of whether the Allen ISH section below is easy to read.

Regional expression figure

Sct regional expression profile

Predicted WMB × fine-CCF profile; not direct full-transcriptome spatial measurement.

Spatial profile

SCO
0.694
MH
0.403
CU
0.314
PG
0.195
PVH
0.193
SNc
0.186
NR
0.152
B
0.147
DR
0.14
VMH
0.138
SUM
0.136
ARH
0.13
VTA
0.128
TRN
0.127
x
0.124
LRNm
0.11
PRP
0.107
PH
0.106
PSTN
0.105
MT
0.105

Evidence and specificity

Evidence status
PREDICTED_FINE
Direct sources
None; predicted localization only
Exclusive threshold
12 positive regions out of 554
Spatial specificity
0.331
Top-region fraction
0.116
Filter status
PASS

Interpretation limits