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General Information
Symbol
Dmel\Nrx-IV
Species
D. melanogaster
Name
Neurexin IV
Annotation Symbol
CG6827
Feature Type
FlyBase ID
FBgn0013997
Gene Model Status
Stock Availability
Gene Snapshot
Neurexin IV (Nrx-IV) encodes a transmembrane protein that is critical for septate junction formation in epithelia and between ensheathing glial cells and neurons. [Date last reviewed: 2019-03-14]
Also Known As

Nrx, NrxIV, nrx IV, neurexin, Dnrx

Key Links
Genomic Location
Cytogenetic map
Sequence location
3L:12,146,519..12,156,990 [+]
Recombination map

3-38

RefSeq locus
NT_037436 REGION:12146519..12156990
Sequence
Other Genome Views
The following external sites may use different assemblies or annotations than FlyBase.
Function
GO Summary Ribbons
Protein Family (UniProt)
Belongs to the neurexin family. (Q94887)
Molecular Function (GO)
[Detailed GO annotations]
Experimental Evidence
-
Predictions / Assertions
-
Summaries
Protein Function (UniProtKB)
Seems to play a role in the formation and function of septate junctions. Septate junctions, which are the equivalent of vertebrates tight junctions, are characterized by regular arrays of transverse structures that span the intermembrane space and form a physical barrier to diffusion. Required for the blood-brain barrier formation.
(UniProt, Q94887)
Summary (Interactive Fly)

multifunctional protein required for structural integrity of septate junctions

Gene Model and Products
Number of Transcripts
2
Number of Unique Polypeptides
2

Please see the GBrowse view of Dmel\Nrx-IV or the JBrowse view of Dmel\Nrx-IV for information on other features

To submit a correction to a gene model please use the Contact FlyBase form

Protein Domains (via Pfam)
Isoform displayed:
Pfam protein domains
InterPro name
classification
start
end
Protein Domains (via SMART)
Isoform displayed:
SMART protein domains
InterPro name
classification
start
end
Comments on Gene Model

Low-frequency RNA-Seq exon junction(s) not annotated.

Gene model reviewed during 5.46

Sequence Ontology: Class of Gene
Transcript Data
Annotated Transcripts
Name
FlyBase ID
RefSeq ID
Length (nt)
Assoc. CDS (aa)
FBtr0075998
4940
1284
FBtr0075999
4940
1284
Additional Transcript Data and Comments
Reported size (kB)

5.0 (northern blot)

Comments
External Data
Crossreferences
Polypeptide Data
Annotated Polypeptides
Name
FlyBase ID
Predicted MW (kDa)
Length (aa)
Theoretical pI
RefSeq ID
GenBank
FBpp0075730
145.5
1284
6.38
FBpp0075731
145.1
1284
6.48
Polypeptides with Identical Sequences

None of the polypeptides share 100% sequence identity.

Additional Polypeptide Data and Comments
Reported size (kDa)

1283 (aa); 150-155 (kD observed); 145 (kD predicted)

Comments
External Data
Subunit Structure (UniProtKB)

The C-terminal region interacts with coracle. Interacts with Patj in cis form. Forms a complex with Nrg and Cont.

(UniProt, Q94887)
Linkouts
Sequences Consistent with the Gene Model
Mapped Features

Click to get a list of regulatory features (enhancers, TFBS, etc.) and gene disruptions (point mutations, indels, etc.) within or overlapping Dmel\Nrx-IV using the Feature Mapper tool.

External Data
Crossreferences
Eukaryotic Promoter Database - A collection of databases of experimentally validated promoters for selected model organisms.
Linkouts
Gene Ontology (21 terms)
Molecular Function (0 terms)
Terms Based on Experimental Evidence (0 terms)
Terms Based on Predictions or Assertions (0 terms)
Biological Process (16 terms)
Terms Based on Experimental Evidence (11 terms)
CV Term
Evidence
References
inferred from mutant phenotype
inferred from mutant phenotype
inferred from mutant phenotype
inferred from mutant phenotype
inferred from mutant phenotype
(assigned by BHF-UCL )
inferred from mutant phenotype
inferred from mutant phenotype
inferred from mutant phenotype
(assigned by BHF-UCL )
Terms Based on Predictions or Assertions (6 terms)
CV Term
Evidence
References
Cellular Component (5 terms)
Terms Based on Experimental Evidence (4 terms)
CV Term
Evidence
References
inferred from direct assay
inferred from high throughput direct assay
inferred from direct assay
(assigned by BHF-UCL )
inferred from direct assay
Terms Based on Predictions or Assertions (2 terms)
CV Term
Evidence
References
inferred from sequence or structural similarity
Expression Data
Expression Summary Ribbons
Colored tiles in ribbon indicate that expression data has been curated by FlyBase for that anatomical location. Colorless tiles indicate that there is no curated data for that location.
For complete stage-specific expression data, view the modENCODE Development RNA-Seq section under High-Throughput Expression below.
Transcript Expression
in situ
Stage
Tissue/Position (including subcellular localization)
Reference
northern blot
Stage
Tissue/Position (including subcellular localization)
Reference
RT-PCR
Stage
Tissue/Position (including subcellular localization)
Reference
Additional Descriptive Data

Both exon 3 and 4 of Nrx-IV are detected via RT-PCR in embryonic glial cells. In embryonic neurons expression of exon 4 is more intense than of exon 3.

Nrx-IV transcripts are differentially expressed in a tissue-specific manner. In late embryos and larvae, Nrx-IV-RA transcript ("exon 4" isoform) is preferentiatially expressed in neurons, while Nrx-IV-RB ("exon 3" isoform) is expressed in glia.

Nrx transcripts are detected on northern blots at all stages of development tested except third instar larvae and peak in 6-18hr embryos. Transcripts are localized by in situ hybridization to epithelial cells of ectodermal origin beginning at embryonic stage 11. This includes cells of the epidermis, tracheal system, pharynx, esophagus, proventriculus, hindgut, salivary glands, PNS and CNS. In the PNS, staining is restricted to the scolopales of the lateral chordotonal organs and is restricted to glial cells. All tissues that express Nrx in the embyro are characterized by the presence of pleated septate junctions (pSJs). Nrx expression is first detected ~1hr before pSJ formation.

Marker for
 
Subcellular Localization
CV Term
Polypeptide Expression
immunolocalization
Stage
Tissue/Position (including subcellular localization)
Reference
mass spectroscopy
Stage
Tissue/Position (including subcellular localization)
Reference
Additional Descriptive Data

Nrx-IV protein is expressed in a short apical stretch of the basolateral membrane of embryonic septate junctions in the embryonic hindgut.

Nrx-IV protein is detected in the glial cell membranes in the peripheral nerves, ensheathing the axons. In the chordotonal organs, it is detected in the scolopale and cap cells.

Nrx protein was detected on all pleated septate junctions documented.

Marker for
Subcellular Localization
CV Term
Evidence
References
inferred from direct assay
inferred from high throughput direct assay
inferred from direct assay
(assigned by BHF-UCL )
inferred from direct assay
Expression Deduced from Reporters
High-Throughput Expression Data
Associated Tools

GBrowse - Visual display of RNA-Seq signals

View Dmel\Nrx-IV in GBrowse 2
RNA-Seq by Region - Search RNA-Seq expression levels by exon or genomic region
Reference
See Gelbart and Emmert, 2013 for analysis details and data files for all genes.
Developmental Proteome: Life Cycle
Developmental Proteome: Embryogenesis
External Data and Images
Linkouts
FLIGHT - Cell culture data for RNAi and other high-throughput technologies
FlyAtlas - Adult expression by tissue, using Affymetrix Dros2 array
Flygut - An atlas of the Drosophila adult midgut
Images
Alleles, Insertions, and Transgenic Constructs
Classical and Insertion Alleles ( 27 )
For All Classical and Insertion Alleles Show
 
Other relevant insertions
Transgenic Constructs ( 40 )
For All Alleles Carried on Transgenic Constructs Show
Transgenic constructs containing/affecting coding region of Nrx-IV
Transgenic constructs containing regulatory region of Nrx-IV
Deletions and Duplications ( 14 )
Phenotypes
For more details about a specific phenotype click on the relevant allele symbol.
Lethality
Allele
Other Phenotypes
Allele
Phenotype manifest in
Allele
anterior fascicle & synapse, with Scer\GAL4elav-C155
anterior fascicle & synapse | supernumerary, with Scer\GAL4elav-C155
axolemma & nerve
embryonic ganglionic branch & embryonic tracheole (with Nrx-IV4025)
embryonic ganglionic branch & embryonic tracheole (with Nrx-IV4865)
scolopidium & abdominal lateral pentascolopidial chordotonal organ lch5
septate junction & peripheral glial cell
Orthologs
Human Orthologs (via DIOPT v7.1)
Homo sapiens (Human) (8)
Species\Gene Symbol
Score
Best Score
Best Reverse Score
Alignment
Complementation?
Transgene?
15 of 15
Yes
Yes
12 of 15
No
Yes
 
12 of 15
No
Yes
12 of 15
No
Yes
12 of 15
No
Yes
12 of 15
No
Yes
3 of 15
No
Yes
1 of 15
No
Yes
Model Organism Orthologs (via DIOPT v7.1)
Mus musculus (laboratory mouse) (8)
Species\Gene Symbol
Score
Best Score
Best Reverse Score
Alignment
Complementation?
Transgene?
15 of 15
Yes
Yes
13 of 15
No
Yes
12 of 15
No
Yes
12 of 15
No
Yes
12 of 15
No
Yes
11 of 15
No
Yes
11 of 15
No
Yes
1 of 15
No
Yes
Rattus norvegicus (Norway rat) (9)
11 of 13
Yes
Yes
11 of 13
Yes
Yes
10 of 13
No
Yes
9 of 13
No
Yes
8 of 13
No
Yes
6 of 13
No
Yes
2 of 13
No
Yes
1 of 13
No
Yes
1 of 13
No
Yes
Xenopus tropicalis (Western clawed frog) (3)
5 of 12
Yes
Yes
5 of 12
Yes
Yes
3 of 12
No
Yes
Danio rerio (Zebrafish) (8)
12 of 15
Yes
Yes
11 of 15
No
Yes
10 of 15
No
Yes
10 of 15
No
Yes
10 of 15
No
Yes
9 of 15
No
Yes
9 of 15
No
Yes
1 of 15
No
Yes
Caenorhabditis elegans (Nematode, roundworm) (2)
11 of 15
Yes
Yes
1 of 15
No
No
Arabidopsis thaliana (thale-cress) (0)
No records found.
Saccharomyces cerevisiae (Brewer's yeast) (0)
No records found.
Schizosaccharomyces pombe (Fission yeast) (0)
No records found.
Orthologs in Drosophila Species (via OrthoDB v9.1) ( EOG091900HL )
Organism
Common Name
Gene
AAA Syntenic Ortholog
Multiple Dmel Genes in this Orthologous Group
Drosophila melanogaster
fruit fly
Drosophila suzukii
Spotted wing Drosophila
Drosophila simulans
Drosophila sechellia
Drosophila erecta
Drosophila yakuba
Drosophila ananassae
Drosophila pseudoobscura pseudoobscura
Drosophila persimilis
Drosophila willistoni
Drosophila virilis
Drosophila mojavensis
Drosophila grimshawi
Orthologs in non-Drosophila Dipterans (via OrthoDB v9.1) ( EOG091500IO )
Organism
Common Name
Gene
Multiple Dmel Genes in this Orthologous Group
Musca domestica
House fly
Glossina morsitans
Tsetse fly
Lucilia cuprina
Australian sheep blowfly
Mayetiola destructor
Hessian fly
Aedes aegypti
Yellow fever mosquito
Anopheles darlingi
American malaria mosquito
Anopheles gambiae
Malaria mosquito
Culex quinquefasciatus
Southern house mosquito
Orthologs in non-Dipteran Insects (via OrthoDB v9.1) ( EOG090W00EM )
Organism
Common Name
Gene
Multiple Dmel Genes in this Orthologous Group
Bombyx mori
Silkmoth
Danaus plexippus
Monarch butterfly
Heliconius melpomene
Postman butterfly
Apis florea
Little honeybee
Apis mellifera
Western honey bee
Bombus impatiens
Common eastern bumble bee
Bombus terrestris
Buff-tailed bumblebee
Linepithema humile
Argentine ant
Megachile rotundata
Alfalfa leafcutting bee
Nasonia vitripennis
Parasitic wasp
Dendroctonus ponderosae
Mountain pine beetle
Tribolium castaneum
Red flour beetle
Pediculus humanus
Human body louse
Rhodnius prolixus
Kissing bug
Cimex lectularius
Bed bug
Acyrthosiphon pisum
Pea aphid
Zootermopsis nevadensis
Nevada dampwood termite
Orthologs in non-Insect Arthropods (via OrthoDB v9.1) ( EOG090X00DN )
Organism
Common Name
Gene
Multiple Dmel Genes in this Orthologous Group
Strigamia maritima
European centipede
Ixodes scapularis
Black-legged tick
Ixodes scapularis
Black-legged tick
Stegodyphus mimosarum
African social velvet spider
Stegodyphus mimosarum
African social velvet spider
Tetranychus urticae
Two-spotted spider mite
Daphnia pulex
Water flea
Orthologs in non-Arthropod Metazoa (via OrthoDB v9.1) ( EOG091G00LF )
Organism
Common Name
Gene
Multiple Dmel Genes in this Orthologous Group
Strongylocentrotus purpuratus
Purple sea urchin
Strongylocentrotus purpuratus
Purple sea urchin
Strongylocentrotus purpuratus
Purple sea urchin
Strongylocentrotus purpuratus
Purple sea urchin
Strongylocentrotus purpuratus
Purple sea urchin
Strongylocentrotus purpuratus
Purple sea urchin
Strongylocentrotus purpuratus
Purple sea urchin
Gallus gallus
Domestic chicken
Gallus gallus
Domestic chicken
Gallus gallus
Domestic chicken
Gallus gallus
Domestic chicken
Gallus gallus
Domestic chicken
Paralogs
Paralogs (via DIOPT v7.1)
Drosophila melanogaster (Fruit fly) (3)
4 of 10
2 of 10
1 of 10
Human Disease Associations
FlyBase Human Disease Model Reports
Disease Model Summary Ribbon
Disease Ontology (DO) Annotations
Models Based on Experimental Evidence ( 1 )
Potential Models Based on Orthology ( 1 )
Modifiers Based on Experimental Evidence ( 1 )
Allele
Disease
Interaction
References
Disease Associations of Human Orthologs (via DIOPT v7.1 and OMIM)
Note that ortholog calls supported by only 1 or 2 algorithms (DIOPT score < 3) are not shown.
Functional Complementation Data
Functional complementation data is computed by FlyBase using a combination of the orthology data obtained from DIOPT and OrthoDB and the allele-level genetic interaction data curated from the literature.
Interactions
Summary of Physical Interactions
esyN Network Diagram
Show neighbor-neighbor interactions:
Select Layout:
Legend:
Protein
RNA
Selected Interactor(s)
Interactions Browser

Please see the Physical Interaction reports below for full details
protein-protein
Physical Interaction
Assay
References
RNA-protein
Physical Interaction
Assay
References
RNA-RNA
Physical Interaction
Assay
References
Summary of Genetic Interactions
esyN Network Diagram
Starting gene(s)
Interaction type
Interacting gene(s)
Reference
Starting gene(s)
Interaction type
Interacting gene(s)
Reference
External Data
Subunit Structure (UniProtKB)
The C-terminal region interacts with coracle. Interacts with Patj in cis form. Forms a complex with Nrg and Cont.
(UniProt, Q94887 )
Linkouts
BioGRID - A database of protein and genetic interactions.
DroID - A comprehensive database of gene and protein interactions.
InterologFinder - Protein-protein interactions (PPI) from both known and predicted PPI data sets.
MIST (protein-protein) - An integrated Molecular Interaction Database
Pathways
Signaling Pathways (FlyBase)
Metabolic Pathways
External Data
Linkouts
Genomic Location and Detailed Mapping Data
Chromosome (arm)
3L
Recombination map

3-38

Cytogenetic map
Sequence location
3L:12,146,519..12,156,990 [+]
FlyBase Computed Cytological Location
Cytogenetic map
Evidence for location
68F6-68F7
Limits computationally determined from genome sequence between P{PZ}rols08232&P{lacW}l(3)j2D3j2D3 and P{PZ}l(3)0508805088
Experimentally Determined Cytological Location
Cytogenetic map
Notes
References
68F-68F
(determined by in situ hybridisation)
Determined by comparing Celera genomic sequence with sequence from BDGP BAC and P1 clones.
Experimentally Determined Recombination Data
Left of (cM)
Right of (cM)
Notes
Stocks and Reagents
Stocks (17)
Genomic Clones (16)
 

Please Note FlyBase no longer curates genomic clone accessions so this list may not be complete

cDNA Clones (79)
 

Please Note This section lists cDNAs and ESTs that fall within the genomic extent of the gene model, which may include cDNAs and ESTs of genes within introns, or of overlapping genes. Please see GBrowse for alignment of the cDNAs and ESTs to the gene model.

cDNA clones, fully sequences
BDGP DGC clones
Other clones
Drosophila Genomics Resource Center cDNA clones

For each fully sequenced cDNA the DGRC maintains various forms of the cDNA (e.g tagged or untagged) in several different host vectors for subsequent cloning and expression in Drosophila and Drosophila cell lines.

cDNA Clones, End Sequenced (ESTs)
BDGP DGC clones
RNAi and Array Information
Linkouts
DRSC - Results frm RNAi screens
GenomeRNAi - A database for cell-based and in vivo RNAi phenotypes and reagents
Antibody Information
Laboratory Generated Antibodies
Commercially Available Antibodies
 
Other Information
Relationship to Other Genes
Source for database identify of

Source for identity of: Nrx CG6827

Source for database merge of
Additional comments
Other Comments

Proper targetting of pck gene product to the pleated septate junctions in the tracheal system depends on Nrx-IV and cora but not Fas3.

dsRNA made from templates generated with primers directed against this gene tested in RNAi screen for effects on Kc167 and S2R+ cell morphology.

The amino-terminal 383 amino acids of cora (a functional domain that is both necessary and sufficient for proper septate junction localisation of cora) and the cytoplasmic domain of Nrx-IV interact directly.

Complementation groups l(3)68Fa, l(3)68Fb, l(3)68Fc, l(3)68Fd, l(3)68Fe, Nrx-IV, l(3)69Aa and l(3)69Ab isolated by Hoogwerf et al. (FBrf0048238) probably correspond to complementation groups l(3)68Fg, l(3)j2D3, l(3)68Fh, rols, l(3)68Fi, Nrx-IV, l(3)69Ah and l(3)69Ai isolated by Baumgartner at al, 1996, Cell 87: 1059--1068, but a one to one correspondence cannot be made as Hoogwerf mutations are apparently lost.

P{nrx+} transformant chromosomes fully rescue the embryonic lethality of l(3)68Ff mutations, demonstrating l(3)68Ff and Nrx-IV are the same complementation group.

Nrx-IV is a transmembrane protein of the septate junction and is required in the formation of septate-junction septa and intercellular barriers.

Identified in a PCR screen for homologues of the vertebrate neurexin.

PCR-primers from the EGF-like region of chicken tenascin have been used to amplify Nrx-IV, Nrx-IV shows high homology to the EGF domain.

Nrx-IV has a transcript of 5.0 kb, and encodes a protein of 1283 aa. The protein has an apparent molecular weight of about 155kD, with a domain structure almost identical to vertebrate neurexin.

Origin and Etymology
Discoverer
Etymology
Identification
External Crossreferences and Linkouts ( 37 )
Sequence Crossreferences
NCBI Gene - Gene integrates information from a wide range of species. A record may include nomenclature, Reference Sequences (RefSeqs), maps, pathways, variations, phenotypes, and links to genome-, phenotype-, and locus-specific resources worldwide.
GenBank Nucleotide - A collection of sequences from several sources, including GenBank, RefSeq, TPA, and PDB.
GenBank Protein - A collection of sequences from several sources, including translations from annotated coding regions in GenBank, RefSeq and TPA, as well as records from SwissProt, PIR, PRF, and PDB.
RefSeq - A comprehensive, integrated, non-redundant, well-annotated set of reference sequences including genomic, transcript, and protein.
UniProt/Swiss-Prot - Manually annotated and reviewed records of protein sequence and functional information
UniProt/TrEMBL - Automatically annotated and unreviewed records of protein sequence and functional information
Other crossreferences
Drosophila Genomics Resource Center - Drosophila Genomics Resource Center (DGRC) cDNA clones
Eukaryotic Promoter Database - A collection of databases of experimentally validated promoters for selected model organisms.
Flygut - An atlas of the Drosophila adult midgut
GenomeRNAi - A database for cell-based and in vivo RNAi phenotypes and reagents
iBeetle-Base - RNAi phenotypes in the red flour beetle (Tribolium castaneum)
KEGG Genes - Molecular building blocks of life in the genomic space.
modMine - A data warehouse for the modENCODE project
Linkouts
BioGRID - A database of protein and genetic interactions.
DroID - A comprehensive database of gene and protein interactions.
DRSC - Results frm RNAi screens
FLIGHT - Cell culture data for RNAi and other high-throughput technologies
FlyAtlas - Adult expression by tissue, using Affymetrix Dros2 array
FlyCyc Genes - Genes from a BioCyc PGDB for Dmel
FlyMine - An integrated database for Drosophila genomics
Interactive Fly - A cyberspace guide to Drosophila development and metazoan evolution
InterologFinder - Protein-protein interactions (PPI) from both known and predicted PPI data sets.
MIST (protein-protein) - An integrated Molecular Interaction Database
Synonyms and Secondary IDs (29)
Reported As
Symbol Synonym
l(3)68Ff
l(3)rsg23
Name Synonyms
rose-gespleten region interval 23
Secondary FlyBase IDs
  • FBgn0002261
Datasets (0)
Study focus (0)
Experimental Role
Project
Project Type
Title
References (257)