RCN3

gene
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Also known as RLP49

Summary

RCN3 (reticulocalbin 3, HGNC:21145) is a protein-coding gene on chromosome 19q13.33, encoding Reticulocalbin-3 (Q96D15). Probable molecular chaperone assisting protein biosynthesis and transport in the endoplasmic reticulum.

Enables calcium ion binding activity. Involved in several processes, including collagen biosynthetic process; positive regulation of peptidase activity; and regulation of phosphatidylinositol 3-kinase/protein kinase B signal transduction. Located in endoplasmic reticulum.

Source: NCBI Gene 57333 — RefSeq curated summary.

At a glance

  • GWAS associations: 12
  • Clinical variants (ClinVar): 63 total
  • MANE Select transcript: NM_020650

Identifiers

Gene identifiers

FieldValue
HGNC IDHGNC:21145
Approved symbolRCN3
Namereticulocalbin 3
Location19q13.33
Locus typegene with protein product
StatusApproved
AliasesRLP49
Ensembl geneENSG00000142552
Ensembl biotypeprotein_coding
OMIM619032
Entrez57333

Gene structure

Transcript identifiers

Ensembl transcripts: 14 — 13 protein_coding, 1 protein_coding_CDS_not_defined

ENST00000270645, ENST00000593483, ENST00000593644, ENST00000597801, ENST00000598833, ENST00000892641, ENST00000892642, ENST00000892643, ENST00000933698, ENST00000933699, ENST00000956869, ENST00000956870, ENST00000956871, ENST00000956872

RefSeq mRNA: 1 — MANE Select: NM_020650 NM_020650

CCDS: CCDS12771

Canonical transcript exons

ENST00000270645 — 7 exons

ExonStartEnd
ENSE000009548714952846749528714
ENSE000009548724953419349534395
ENSE000009548734953703349537205
ENSE000009548744953911949539179
ENSE000009548754954255349542752
ENSE000012899104952800349528058
ENSE000031100084954310649543633

Expression profiles

Bgee: expression breadth ubiquitous, 259 present calls, max score 99.20.

FANTOM5 (CAGE): breadth ubiquitous, TPM avg 44.6813 / max 1181.9112, expressed in 1165 samples.

FANTOM5 promoters (2 alternative TSS)

Promoter IDTPM avgSamples expressed
17701943.28231161
1770201.3990491

Top tissues by expression

285 total, by Bgee expression score (0-100, higher = more expressed):

TissueAnatomy IDExpression scoreQuality
stromal cell of endometriumCL:000225599.20gold quality
mucosa of transverse colonUBERON:000499197.81gold quality
ascending aortaUBERON:000149697.36gold quality
thoracic aortaUBERON:000151597.30gold quality
descending thoracic aortaUBERON:000234596.71gold quality
right coronary arteryUBERON:000162596.21gold quality
left coronary arteryUBERON:000162695.83gold quality
cartilage tissueUBERON:000241895.79gold quality
tendon of biceps brachiiUBERON:000818895.72gold quality
endocervixUBERON:000045895.71gold quality
coronary arteryUBERON:000162195.02gold quality
omental fat padUBERON:001041494.83gold quality
peritoneumUBERON:000235894.77gold quality
right lobe of liverUBERON:000111494.76gold quality
right ovaryUBERON:000211894.22gold quality
aortaUBERON:000094794.21gold quality
adipose tissue of abdominal regionUBERON:000780893.84gold quality
calcaneal tendonUBERON:000370193.76gold quality
small intestine Peyer’s patchUBERON:000345493.62gold quality
body of uterusUBERON:000985393.49gold quality
ectocervixUBERON:001224993.29gold quality
transverse colonUBERON:000115793.15gold quality
spleenUBERON:000210693.12gold quality
left ovaryUBERON:000211993.12gold quality
tibial nerveUBERON:000132392.77gold quality
apex of heartUBERON:000209892.62gold quality
right atrium auricular regionUBERON:000663192.61gold quality
tendonUBERON:000004392.59gold quality
subcutaneous adipose tissueUBERON:000219092.10gold quality
popliteal arteryUBERON:000225092.04gold quality

Single-cell (SCXA)

Detected in 7 experiment(s), a significant marker in 7.

ExperimentMarker?Max mean expression
E-MTAB-10287yes103.86
E-HCAD-1yes74.85
E-MTAB-8410yes38.75
E-HCAD-10yes29.19
E-ANND-3yes19.57
E-CURD-112yes18.09
E-MTAB-5061yes11.93

Regulation

Is transcription factor: no

miRNA regulators (miRDB)

32 targeting RCN3, top 30 by miRDB confidence (max_score; target_count = how many genes the miRNA targets in total — lower means more specific):

miRNAMax scoreAvg scoremiRNA target_count
HSA-MIR-6721-5P99.9368.922981
HSA-MIR-311999.9271.342390
HSA-MIR-449299.8768.253611
HSA-MIR-137-3P99.8774.742401
HSA-MIR-221-5P99.8665.451052
HSA-MIR-807399.8665.211118
HSA-MIR-6842-5P99.8067.541587
HSA-MIR-7110-5P99.8067.841712
HSA-MIR-6764-5P99.7567.892304
HSA-MIR-6887-3P99.6667.831778
HSA-MIR-24-3P99.5969.971934
HSA-MIR-1915-3P99.5866.791988
HSA-MIR-127599.4767.902749
HSA-MIR-6791-5P99.1665.921844
HSA-MIR-429299.1665.571767
HSA-MIR-6884-5P99.1064.501987
HSA-MIR-485-5P99.1064.781889
HSA-MIR-66199.0965.942062
HSA-MIR-5001-5P99.0566.761972
HSA-MIR-319698.9663.91326
HSA-MIR-4755-3P98.7765.591915
HSA-MIR-1227-5P98.6565.321549
HSA-MIR-990398.4766.70748
HSA-MIR-318098.4664.68348
HSA-MIR-3180-3P98.4664.68348
HSA-MIR-6816-5P98.4664.35364
HSA-MIR-6829-3P97.4564.311137
HSA-MIR-2467-5P97.3667.71991
HSA-MIR-6836-3P97.0864.99712
HSA-MIR-6762-5P96.5564.62972

Literature-anchored findings (GeneRIF, showing 6)

  • Autoactivation & secretion of rat PACE4 was increased upon co-expression with recombinant human RCN-3. Selective and transient association of RCN-3 with the precursor of PACE4 plays an important role in the biosynthesis of PACE4. (PMID:16433634)
  • RCN3 expression in systemic sclerosis was not statistically significantly different to healthy controls. (PMID:27468573)
  • Study identified reticulocalbin-3 (RCN-3) as a common molecule down-regulated by aldosterone (Aldo), galectin-3 and cardiotrophin-1 - key factors in the cardiac remodeling induced by Aldo associated with cardiac hypertrophy and fibrosis. Moreover, RCN-3 emerges as a new potential negative regulator of collagen production. (PMID:28939891)
  • genome-wide association study in US: Data suggest, among white subjects, an SNP in RCN3 (rs34459162) and a missense mutation in GCKR (rs1260236) are associated with serum levels of glycated albumin; among black subjects, an intergenic SNP in PRKCA (rs2438321) is associated with fructosamine levels and intronic variant in PRKCA (rs59443763) is associated with glycated albumin levels. (GCKR = glucokinase regulatory protein) (PMID:29844224)
  • Rcn3 Suppression Was Responsible for Partial Relief of Emphysema as Shown by Specific Type II Alveolar Epithelial Cell Rcn3 CKO Mouse Model. (PMID:33531801)
  • An Expanded Genome-Wide Association Study of Fructosamine Levels Identifies RCN3 as a Replicating Locus and Implicates FCGRT as the Effector Transcript. (PMID:34753797)

Cross-species orthologs

5 orthologs

OrganismSymbolGene ID
danio_reriorcn3ENSDARG00000037961
mus_musculusRcn3ENSMUSG00000019539
rattus_norvegicusRcn3ENSRNOG00000043007
drosophila_melanogasterscfFBGN0025682
caenorhabditis_elegansWBGENE00019760

Paralogs (4): RCN1 (ENSG00000049449), SDF4 (ENSG00000078808), RCN2 (ENSG00000117906), CALU (ENSG00000128595)

Protein

Protein identifiers

Reticulocalbin-3Q96D15 (reviewed: Q96D15)

Alternative names: EF-hand calcium-binding protein RLP49

All UniProt accessions (4): Q96D15, M0QYB8, M0QZH0, M0QZU3

UniProt curated annotations — full annotation on UniProt →

Function. Probable molecular chaperone assisting protein biosynthesis and transport in the endoplasmic reticulum. Required for the proper biosynthesis and transport of pulmonary surfactant-associated protein A/SP-A, pulmonary surfactant-associated protein D/SP-D and the lipid transporter ABCA3. By regulating both the proper expression and the degradation through the endoplasmic reticulum-associated protein degradation pathway of these proteins plays a crucial role in pulmonary surfactant homeostasis. Has an anti-fibrotic activity by negatively regulating the secretion of type I and type III collagens. This calcium-binding protein also transiently associates with immature PCSK6 and regulates its secretion.

Subunit / interactions. Interacts with PCSK6 (immature form including the propeptide); probably involved in the maturation and the secretion of PCSK6.

Subcellular location. Endoplasmic reticulum lumen.

Tissue specificity. Widely expressed.

Post-translational modifications. Degraded by PCSK6 and other endoproteases including FURIN and PCSK5. N-glycosylated.

Induction. Down-regulated by aldosterone (at protein level). No effect at the transcript level.

Similarity. Belongs to the CREC family.

RefSeq proteins (1): NP_065701* (*=MANE)

Domains & families (InterPro)

IDNameType
IPR002048EF_hand_domDomain
IPR011992EF-hand-dom_pairHomologous_superfamily
IPR018247EF_Hand_1_Ca_BSBinding_site

Pfam: PF13202, PF13499

UniProt features (46 total): binding site 29, domain 6, mutagenesis site 3, sequence conflict 2, signal peptide 1, chain 1, glycosylation site 1, sequence variant 1, region of interest 1, short sequence motif 1

Structure

Experimental structures (PDB)

0 structures.

Predicted structure (AlphaFold)

ModelpLDDTFraction very-high
AF-Q96D15-F182.890.58

Functional residue map

Curated UniProt residues grouped by drug-discovery relevance — catalytic, ligand-binding, modification, and mutation-validated positions. Source: UniProtKB sequence features.

Ligand- & substrate-binding residues (29): 92; 94; 96; 101; 126; 128; 130; 132; 137; 176; 178; 180

Glycosylation sites (1): 140

Mutagenesis-validated functional residues (3):

PositionPhenotype
86decreased function in pcsk6 maturation and/or secretion.
112decreased function in pcsk6 maturation and/or secretion.
325–328decreased function in pcsk6 maturation and/or secretion.

Function

Pathways and Gene Ontology

Reactome pathways

0 pathways

MSigDB gene sets: 161 (showing top): RRAGTTGT_UNKNOWN, GOBP_RESPONSE_TO_NITROGEN_COMPOUND, GOBP_EPITHELIUM_DEVELOPMENT, GOBP_LUNG_EPITHELIUM_DEVELOPMENT, GOBP_RESPONSE_TO_ENDOPLASMIC_RETICULUM_STRESS, GOBP_MACROMOLECULE_CATABOLIC_PROCESS, GNF2_PTX3, AACWWCAANK_UNKNOWN, GOBP_LIPID_HOMEOSTASIS, GOBP_POSITIVE_REGULATION_OF_CATALYTIC_ACTIVITY, GOBP_REGULATION_OF_HYDROLASE_ACTIVITY, GOBP_POSITIVE_REGULATION_OF_MOLECULAR_FUNCTION, GOBP_PHOSPHATIDYLINOSITOL_3_KINASE_PROTEIN_KINASE_B_SIGNAL_TRANSDUCTION, GOBP_REGULATION_OF_PEPTIDASE_ACTIVITY, GOBP_POSITIVE_REGULATION_OF_PEPTIDASE_ACTIVITY

GO Biological Process (9): protein secretion (GO:0009306), positive regulation of peptidase activity (GO:0010952), protein transport (GO:0015031), collagen biosynthetic process (GO:0032964), ERAD pathway (GO:0036503), surfactant homeostasis (GO:0043129), regulation of phosphatidylinositol 3-kinase/protein kinase B signal transduction (GO:0051896), phospholipid homeostasis (GO:0055091), lung epithelium development (GO:0060428)

GO Molecular Function (3): calcium ion binding (GO:0005509), protein binding (GO:0005515), metal ion binding (GO:0046872)

GO Cellular Component (2): endoplasmic reticulum (GO:0005783), endoplasmic reticulum lumen (GO:0005788)

GO top-level categories

Rollup of top GO terms by namespace:

CategoryTerms
protein transport1
secretion by cell1
establishment of protein localization to extracellular region1
protein localization to extracellular region1
peptidase activity1
positive regulation of proteolysis1
positive regulation of hydrolase activity1
regulation of peptidase activity1
transport1
intracellular protein localization1
establishment of protein localization1
biosynthetic process1
collagen metabolic process1
proteasomal protein catabolic process1
response to endoplasmic reticulum stress1
response to chemical1
multicellular organismal-level chemical homeostasis1
phosphatidylinositol 3-kinase/protein kinase B signal transduction1
regulation of intracellular signal transduction1
lipid homeostasis1
lung development1
epithelium development1
metal ion binding1
binding1
cation binding1
cytoplasm1
endomembrane system1
intracellular membrane-bounded organelle1
endoplasmic reticulum1
intracellular organelle lumen1

Protein interactions and networks

STRING

582 interactions, top by confidence (×1000):

Protein AProtein BPartner UniProtScore
RCN3PRRG2O14669495
RCN3NOSIPQ9Y314452
RCN3EIF3IQ13347423
RCN3LURAP1Q96LR2405
RCN3FKBP9O95302400
RCN3RPL13AP40429376
RCN3SRLQ86TD4376
RCN3A0A087WVV2A0A087WVV2371
RCN3SH3BGRL3Q9H299346
RCN3FAM234BA2RU67339
RCN3NARS2Q96I59335
RCN3RNF181Q9P0P0327
RCN3FKBP10Q96AY3323
RCN3PSMB2P31145322
RCN3CPN2P22792308

IntAct

41 interactions, top by confidence:

ABTypeScore
RCN3SUFUpsi-mi:“MI:0915”(physical association)0.700
SUFURCN3psi-mi:“MI:0915”(physical association)0.700
MBD3RCN3psi-mi:“MI:0915”(physical association)0.560
RCN3PACRGLpsi-mi:“MI:0915”(physical association)0.560
PACRGLRCN3psi-mi:“MI:0915”(physical association)0.560
ZNF417RCN3psi-mi:“MI:0915”(physical association)0.560
DNAAF19RCN3psi-mi:“MI:0915”(physical association)0.560
MYO15BRCN3psi-mi:“MI:0915”(physical association)0.560
NAA10RCN3psi-mi:“MI:0915”(physical association)0.560
PIPTBKBP1psi-mi:“MI:0914”(association)0.530
RCN3STAT6psi-mi:“MI:0915”(physical association)0.370
RCN3MKNK1psi-mi:“MI:0915”(physical association)0.370
RCN3PRUNE2psi-mi:“MI:0915”(physical association)0.370
RCN3HID1psi-mi:“MI:0915”(physical association)0.370
RCN3KLHL42psi-mi:“MI:0915”(physical association)0.370
RCN3psi-mi:“MI:0915”(physical association)0.370
XRCC3DERL1psi-mi:“MI:0914”(association)0.350
SNAP23psi-mi:“MI:0914”(association)0.350
EMID1NDUFS4psi-mi:“MI:0914”(association)0.350
POMGNT2FAM83Gpsi-mi:“MI:0914”(association)0.350
RNASE3RNASEH1psi-mi:“MI:0914”(association)0.350
SCCPDHIPO5psi-mi:“MI:0914”(association)0.350
SUFURCN3psi-mi:“MI:0915”(physical association)0.000
MBD3RCN3psi-mi:“MI:0915”(physical association)0.000

BioGRID (31): RCN3 (Two-hybrid), PACRGL (Two-hybrid), PRUNE2 (Two-hybrid), RCN3 (Two-hybrid), HID1 (Two-hybrid), KLHL42 (Two-hybrid), RCN3 (Affinity Capture-Western), RCN3 (Affinity Capture-MS), RCN3 (Affinity Capture-MS), RCN3 (Co-fractionation), RCN3 (Two-hybrid), RCN3 (Two-hybrid), RCN3 (Two-hybrid), CCDC103 (Two-hybrid), ZNF417 (Two-hybrid)

ESM2 similar proteins: A0A6I8RMG7, A0AVX7, A2VEI2, A4IG32, A5D7A0, B5X186, B5X4E0, I6L9G5, J3S9D9, O35783, O35887, O93390, O93434, P07214, P09486, P13213, P16975, P20112, P22676, P36377, P36378, P41044, P49257, P61022, P61023, P79881, Q05186, Q14257, Q15293, Q28BT4, Q2KJ39, Q3T0K1, Q4U471, Q5R767, Q5R7F0, Q5ZM44, Q62703, Q62902, Q6IP82, Q6IQP3

Diamond homologs: B5X186, B5X4E0, I6L9G5, J3S9D9, O35783, O35887, O43852, O93434, P02597, P04464, Q05186, Q14257, Q15293, Q28BT4, Q2KJ39, Q3T0K1, Q4U471, Q5RDD8, Q62703, Q66JA6, Q6IP82, Q6IQP3, Q6XLQ7, Q7SXV9, Q8BH97, Q8BP92, Q96D15, Q9FKW4, P42529, Q5ZKE5, Q03975, Q9M7R0

SIGNOR signaling

0 interactions.

Disease & clinical

Clinical variants and AI predictions

ClinVar

63 variants total. Per-class counts are floors (≥ shown; pagination cap):

ClassificationCount (floor)
Pathogenic0
Likely pathogenic0
Uncertain significance50
Likely benign2
Benign0

Top pathogenic / likely-pathogenic (0)

SpliceAI

1157 predictions. Top by Δscore:

VariantEffectΔscore
19:49528057:GG:Gdonor_gain1.0000
19:49528058:GG:Gdonor_gain1.0000
19:49528065:G:GTdonor_gain1.0000
19:49528695:G:GTdonor_gain1.0000
19:49528696:A:Tdonor_gain1.0000
19:49528712:GGG:Gdonor_gain1.0000
19:49528713:GG:Gdonor_gain1.0000
19:49528713:GGG:Gdonor_gain1.0000
19:49528714:GG:Gdonor_gain1.0000
19:49528715:G:GGdonor_gain1.0000
19:49528715:G:Tdonor_loss1.0000
19:49528716:T:Adonor_loss1.0000
19:49534191:AGGCG:Aacceptor_gain1.0000
19:49534192:GGCGG:Gacceptor_gain1.0000
19:49537028:CCCAG:Cacceptor_loss1.0000
19:49537031:A:AGacceptor_gain1.0000
19:49537031:AG:Aacceptor_gain1.0000
19:49537032:G:GAacceptor_gain1.0000
19:49537032:GG:Gacceptor_gain1.0000
19:49537032:GGT:Gacceptor_gain1.0000
19:49537032:GGTGA:Gacceptor_gain1.0000
19:49537201:TTGCT:Tdonor_gain1.0000
19:49537202:TGCTG:Tdonor_loss1.0000
19:49537203:GCT:Gdonor_gain1.0000
19:49537204:CT:Cdonor_gain1.0000
19:49537204:CTGT:Cdonor_loss1.0000
19:49537205:TGTG:Tdonor_loss1.0000
19:49537206:G:GGdonor_gain1.0000
19:49537206:GTG:Gdonor_loss1.0000
19:49537207:T:Adonor_loss1.0000

AlphaMissense

2162 scored. Top likely-pathogenic:

VariantProtein changeam_pathogenicity
19:49542596:G:CW241C1.000
19:49542596:G:TW241C1.000
19:49542727:T:CL285P1.000
19:49543152:T:CF309S1.000
19:49543152:T:GF309C1.000
19:49534255:T:CL102P0.999
19:49537101:T:CF172L0.999
19:49537102:T:CF172S0.999
19:49537103:C:AF172L0.999
19:49537103:C:GF172L0.999
19:49537111:C:AA175D0.999
19:49537150:T:CL188P0.999
19:49539159:T:AV220D0.999
19:49542594:T:AW241R0.999
19:49542594:T:CW241R0.999
19:49542618:T:CF249L0.999
19:49542619:T:CF249S0.999
19:49542619:T:GF249C0.999
19:49542620:C:AF249L0.999
19:49542620:C:GF249L0.999
19:49542680:G:CW269C0.999
19:49542680:G:TW269C0.999
19:49542717:G:CA282P0.999
19:49542723:C:GH284D0.999
19:49543151:T:CF309L0.999
19:49543153:T:AF309L0.999
19:49543153:T:GF309L0.999
19:49543160:A:CS312R0.999
19:49543162:T:AS312R0.999
19:49543162:T:GS312R0.999

dbSNP variants (sampled 300 via entrez): RS1000196721 (19:49532378 T>G), RS1000248030 (19:49529403 A>G,T), RS1000356116 (19:49540893 G>A,T), RS1000376443 (19:49535002 C>T), RS1000930793 (19:49539382 A>C), RS1001179655 (19:49526866 C>T), RS1001584499 (19:49534640 A>G), RS1001660000 (19:49534392 C>A,G,T), RS1001804090 (19:49539878 A>C), RS1002056313 (19:49528301 C>A,T), RS1002122534 (19:49531229 G>A), RS1002168104 (19:49540201 G>T), RS1002188351 (19:49535229 A>G,T), RS1002463358 (19:49540392 G>A), RS1002665838 (19:49533231 C>G)

Disease associations

OMIM: gene MIM:619032 | disease phenotypes:

GenCC curated gene-disease

Mondo (0):

Orphanet (0):

HPO phenotypes

0 total (0 of 0 shown, HPO-id order):

GWAS associations

12 associations (top):

StudyTraitp-value
GCST000583_10Hematological and biochemical traits3.000000e-08
GCST002539_91Schizophrenia5.000000e-08
GCST004615_127Hemoglobin concentration1.000000e-11
GCST006056_1Fructosamine levels5.000000e-09
GCST006058_1Total glycated albumin levels4.000000e-08
GCST008839_380Height4.000000e-10
GCST010241_67Apolipoprotein A1 levels5.000000e-14
GCST012619_1Fructosamine levels6.000000e-11
GCST90002383_292Hematocrit4.000000e-13
GCST90002384_461Hemoglobin1.000000e-10
GCST90002397_437Mean spheric corpuscular volume2.000000e-11
GCST90017143_1Fructosamine levels5.000000e-11

EFO canonical traits (6, from GWAS)

EFO IDTrait name
EFO:0004747protein measurement
EFO:0004509hemoglobin measurement
EFO:0009303fructosamine measurement
EFO:0009305total glycated albumin
EFO:0004614apolipoprotein A 1 measurement
EFO:0004348hematocrit

Drugs & pharmacology

Drug and pharmacology data

Is drug target: no

PharmGKB: 1 entry (VIP=true, CPIC=false)

CTD chemical–gene interactions

43 total (human), top 30 by PubMed support.

ChemicalActions (top 5)PubMed papers
Valproic Acidaffects cotreatment, increases expression, affects expression, increases methylation6
Air Pollutantsincreases abundance, decreases expression, increases expression, affects expression3
tobacco tardecreases expression, decreases reaction2
Benzo(a)pyrenedecreases expression, increases methylation2
Tobacco Smoke Pollutiondecreases expression, affects expression2
Aflatoxin B1increases methylation, decreases expression2
Particulate Matterdecreases expression, increases abundance, increases expression2
aristolochic acid Iincreases expression1
triphenyl phosphateaffects expression1
propionaldehydeincreases expression1
bisphenol Adecreases expression1
sodium arsenatedecreases expression1
tris(2-butoxyethyl) phosphateaffects expression1
tris(1,3-dichloro-2-propyl)phosphatedecreases expression1
sodium arseniteincreases expression1
butyraldehydeincreases expression1
benzo(e)pyrenedecreases methylation1
diallyl disulfidedecreases expression, decreases reaction1
pentanalincreases expression1
perfluorooctane sulfonic acidincreases expression1
entinostatincreases expression1
4-(5-benzo(1,3)dioxol-5-yl-4-pyridin-2-yl-1H-imidazol-2-yl)benzamideaffects cotreatment, increases expression1
bisphenol Bincreases expression1
abrinedecreases expression1
dorsomorphinaffects cotreatment, increases expression1
bisphenol Sincreases expression1
bisphenol AFincreases expression1
Arsenic Trioxideincreases expression1
Acetaminophendecreases expression1
Aldehydesincreases expression1

Clinical trials (associated diseases)

0 trials via MONDO — disease-level, not drug-specific.

No linked Atlas pages yet — the cross-entity mesh grows as the corpus expands.