FB2026_01 , released March 12, 2026
FB2026_01 , released March 12, 2026
Gene: Dmel\numb
Open Close
General Information
Symbol
Dmel\numb
Species
D. melanogaster
Name
numb
Annotation Symbol
CG3779
Feature Type
FlyBase ID
FBgn0002973
Gene Model Status
Stock Availability
Gene Summary
numb (numb) encodes a membrane-associated inhibitor of Notch signaling. It controls neuroblast and sense organ precursor asymmetric division. It is asymmetrically localized during mitosis and segregates exclusively to one of two daughter cells. [Date last reviewed: 2019-03-14] (FlyBase Gene Snapshot)
Also Known As

nb, l(2)03235, dNumb

Key Links
Genomic Location
Cytogenetic map
Sequence location
Recombination map
2-35
RefSeq locus
NT_033779 REGION:9437469..9464184
Sequence
Genomic Maps
Other Genome Views
The following external sites may use different assemblies or annotations than FlyBase.
Function
Gene Ontology (GO) Annotations (27 terms)
Molecular Function (2 terms)
Terms Based on Experimental Evidence (2 terms)
CV Term
Evidence
References
inferred from direct assay
inferred from physical interaction with UniProtKB:Q9VDG2
inferred from physical interaction with FLYBASE:Nak; FB:FBgn0015772
inferred from physical interaction with FLYBASE:mol; FB:FBgn0086711
inferred from physical interaction with FLYBASE:spdo; FB:FBgn0260440
Terms Based on Predictions or Assertions (0 terms)
Biological Process (22 terms)
Terms Based on Experimental Evidence (22 terms)
CV Term
Evidence
References
inferred from mutant phenotype
inferred from mutant phenotype
inferred from genetic interaction with FLYBASE:jumu; FB:FBgn0015396
inferred from genetic interaction with FLYBASE:CHES-1-like; FB:FBgn0029504
inferred from mutant phenotype
inferred from mutant phenotype
inferred from mutant phenotype
inferred from mutant phenotype
inferred from mutant phenotype
inferred from mutant phenotype
inferred from mutant phenotype
inferred from mutant phenotype
inferred from mutant phenotype
inferred from mutant phenotype
inferred from mutant phenotype
inferred from mutant phenotype
inferred from mutant phenotype
inferred from mutant phenotype
inferred from mutant phenotype
inferred from mutant phenotype
inferred from direct assay
inferred from mutant phenotype
Terms Based on Predictions or Assertions (0 terms)
Cellular Component (3 terms)
Terms Based on Experimental Evidence (2 terms)
CV Term
Evidence
References
located_in cell cortex
inferred from direct assay
located_in cytoplasm
inferred from direct assay
Terms Based on Predictions or Assertions (1 term)
CV Term
Evidence
References
traceable author statement
Gene Group (FlyBase)
Protein Family (UniProt)
-
Summaries
Gene Snapshot
numb (numb) encodes a membrane-associated inhibitor of Notch signaling. It controls neuroblast and sense organ precursor asymmetric division. It is asymmetrically localized during mitosis and segregates exclusively to one of two daughter cells. [Date last reviewed: 2019-03-14]
Pathway (FlyBase)
NEGATIVE REGULATORS OF NOTCH SIGNALING PATHWAY -
The Notch receptor signaling pathway is activated by the binding of the transmembrane receptor Notch (N) to transmembrane ligands, Dl or Ser, presented on adjacent cells. This results in the proteolytic cleavage of N, releasing the intracellular domain (NICD). NICD translocates into the nucleus, interacting with Su(H) and mam to form a transcription complex, which up-regulates transcription of Notch-responsive genes. Negative regulators of the pathway down-regulate the signal from the sending cell or the response in the receiving cell. (Adapted from FBrf0225731 and FBrf0192604).
Protein Function (UniProtKB)
Required in determination of cell fate during sensory organ formation in embryos (PubMed:2752427). Restricts developmental potential and promote maturation of intermediary neuronal progenitor (INP) cells probably acting as an antagonist of Notch signaling (PubMed:18342578, PubMed:24550111, PubMed:28899667).
(UniProt, P16554)
Phenotypic Description (Red Book; Lindsley and Zimm 1992)
numb: numb
The numb gene must be able to function in the Drosophila embryo in order for the peripheral sensory neurons to acquire their correct identity. In the mutants, the precursors of neurons and glial cells in the external sensory (es) organs are, for the most part, transformed into nonneural support cells; some of the es organs are duplicated. Transformation of neuron precursors into nonneural cells also occurs in the chordotonal (ch) organs. Precursors of the multiple dendrite (md) neurons undergo similar changes. Muscle development is abnormal in numb mutant alleles; some muscles are fewer in number than in wild type and show pattern changes (Uemura et al.).
Summary (Interactive Fly)

signaling protein - targeted by Notch signaling - involved in determination of alternate cell fates - regulates the balance between Notch recycling and late endosome targeting in neural progenitor cells

Gene Model and Products
Number of Transcripts
3
Number of Unique Polypeptides
2

Please see the JBrowse view of Dmel\numb 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
Structure
Protein 3D structure   (Predicted by AlphaFold)   (AlphaFold entry P16554)

If you don't see a structure in the viewer, refresh your browser.
Model Confidence:
  • Very high (pLDDT > 90)
  • Confident (90 > pLDDT > 70)
  • Low (70 > pLDDT > 50)
  • Very low (pLDDT < 50)

AlphaFold produces a per-residue confidence score (pLDDT) between 0 and 100. Some regions with low pLDDT may be unstructured in isolation.

Experimentally Determined Structures
Crossreferences
PDB - An information portal to biological macromolecular structures
Comments on Gene Model

Gene model reviewed during 5.44

Annotated transcripts do not represent all supported alternative splices within 5' UTR.

Gene model reviewed during 5.46

Gene model reviewed during 5.49

Tissue-specific extension of 3' UTRs observed during later stages (FBrf0218523, FBrf0219848); all variants may not be annotated

Transcript Data
Annotated Transcripts
Name
FlyBase ID
RefSeq ID
Length (nt)
Assoc. CDS (aa)
FBtr0079822
3309
556
FBtr0079821
2956
515
FBtr0339526
4395
556
Additional Transcript Data and Comments
Reported size (kB)

3.5, 3.1 (northern blot)

Comments
External Data
Crossreferences
Polypeptide Data
Annotated Polypeptides
Name
FlyBase ID
Predicted MW (kDa)
Length (aa)
Theoretical pI
UniProt
RefSeq ID
GenBank
FBpp0079420
60.6
556
10.15
FBpp0079419
56.1
515
9.38
FBpp0308609
60.6
556
10.15
Polypeptides with Identical Sequences

The group(s) of polypeptides indicated below share identical sequence to each other.

556 aa isoforms: numb-PA, numb-PD
Additional Polypeptide Data and Comments
Reported size (kDa)

556, 515 (aa); 61, 56 (kD predicted)

Comments

The phosphotyrosine binding domains (PID) of most polypeptides studied preferentially bind peptides containing an NPXpY motif (X = any amino acid), whereas the the PID of numb protein binds peptides with a "YIGPY#" motif (# = a hydrophobic amino acid). The affinity of the PID domain for the peptide increases when the second tyrosine is phosphorylated. The GP(p)Y core motif is required for high-affinity binding. The same amino acids in the numb PID are likely to bind both the phosphorylated and non-phosphorylated forms of the peptide.

External Data
Subunit Structure (UniProtKB)

Interacts with Nak.

(UniProt, P16554)
Post Translational Modification

Phosphorylated by aPKC which lowers lipid affinity and promotes dissociation from the cell cortex.

(UniProt, P16554)
Domain

PTB domain recognizes multiple ligands by engaging different amounts of surface area dictated by tertiary contacts rather than primary sequence. This may allow interactions with a diverse set of proteins during asymmetric division and specification of cell fate.

The phospho-regulated basic and hydrophobic (PRBH) motif is necessary and sufficient for interaction with phospholipids permitting cortical localization (PubMed:26481050). Phosphorylation of the PRBH motif by aPKC inhibits the association of the protein with the cortical membrane (PubMed:26481050).

(UniProt, P16554)
Crossreferences
InterPro - A database of protein families, domains and functional sites
PDB - An information portal to biological macromolecular structures
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\numb using the Feature Mapper tool.

External Data
Crossreferences
Eukaryotic Promoter Database - A collection of databases of experimentally validated promoters for selected model organisms.
Linkouts
Expression Data
Testis-specificity index

The testis specificity index was calculated from modENCODE tissue expression data by Vedelek et al., 2018 to indicate the degree of testis enrichment compared to other tissues. Scores range from -2.52 (underrepresented) to 5.2 (very high testis bias).

-0.09

Transcript Expression
immunolocalization
Stage
Tissue/Position (including subcellular localization)
Reference
in situ
Stage
Tissue/Position (including subcellular localization)
Reference
organism

Comment: maternally deposited

antennal anlage

Comment: reported as procephalic ectoderm anlage

central brain anlage

Comment: reported as procephalic ectoderm anlage

dorsal head epidermis anlage

Comment: reported as procephalic ectoderm anlage

visual anlage

Comment: reported as procephalic ectoderm anlage

northern blot
Stage
Tissue/Position (including subcellular localization)
Reference

Comment: reference states 0-3 hr AEL

Comment: reference states >=3 hr AEL

Additional Descriptive Data
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
western blot
Stage
Tissue/Position (including subcellular localization)
Reference

Comment: reference states 0-5 hr AEL

Comment: reference states 3-17 hr AEL

Additional Descriptive Data

numb protein associates with the plasma membrane of the sensory organ precursor cell and of the neuroblast, and is asymmetrically localized.

numb protein is homogenously distributed along the plasma membrane during interphase and early prophase in embryonic neuroblasts. Beginning in late prophase, numb forms a crescent overlying one of two centromeres and remains in this crescent through later stages of mitosis. During telophase, it segregates into one of the two daughter cells where it is found evenly distributed along the plasma membrane. numb protein localization is microtubule and actin independent.

numb protein localizes in a ring along the plasma membrane of the sensory organ precursor cell, and is distributed asymmetrically to the daughter cell. During neuroblast division, numb protein is asymmetrically localized in the neuroblast, and segregates into the ganglion mother cell. Expression is also detected in epidermal cell membranes.

An antibody against numb protein detects a 60 kD protein, presumed to be the product of the maternal transcript, in 0-2 hr and 3-5 hr embryos.

Marker for
 
Subcellular Localization
CV Term
Evidence
References
located_in cell cortex
inferred from direct assay
located_in cytoplasm
inferred from direct assay
Expression Deduced from Reporters
High-Throughput Expression Data
Associated Tools

JBrowse - Visual display of RNA-Seq signals

View Dmel\numb in JBrowse
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
BDGP expression data - Patterns of gene expression in Drosophila embryogenesis
DRscDB - A single-cell RNA-seq resource for data mining and data comparison across species
EMBL-EBI Single Cell Expression Atlas - Single cell expression across species
FlyAtlas - Adult expression by tissue, using Affymetrix Dros2 array
FlyAtlas2 - A Drosophila melanogaster expression atlas with RNA-Seq, miRNA-Seq and sex-specific data
Fly-FISH - A database of Drosophila embryo and larvae mRNA localization patterns
Flygut - An atlas of the Drosophila adult midgut
Images
FlyExpress - Embryonic expression images (BDGP data)
  • Stages(s) 1-3
  • Stages(s) 4-6
  • Stages(s) 7-8
  • Stages(s) 9-10
  • Stages(s) 11-12
  • Stages(s) 13-16
Alleles, Insertions, Transgenic Constructs, and Aberrations
Classical and Insertion Alleles ( 60 )
For All Classical and Insertion Alleles Show
 
Other relevant insertions
Transgenic Constructs ( 60 )
For All Alleles Carried on Transgenic Constructs Show
Transgenic constructs containing/affecting coding region of numb
Transgenic constructs containing regulatory region of numb
Aberrations (Deficiencies and Duplications) ( 30 )
Inferred from experimentation ( 30 )
Inferred from location ( 7 )
Variants
Variant Molecular Consequences
Alleles Representing Disease-Implicated Variants
Phenotypes
For more details about a specific phenotype click on the relevant allele symbol.
Lethality
Allele
Sterility
Allele
Other Phenotypes
Allele
Phenotype manifest in
Allele
chemosensory sensory organ & wing vein L1 & glial cell | supernumerary
chemosensory sensory organ & wing vein L3 & glial cell | supernumerary
embryonic peripheral nervous system & glial cell | supernumerary
embryonic peripheral nervous system & neuron
fascicle & antennal segment 3, with Scer\GAL4sca-P309
glial cell & antennal segment 3 | ectopic, with Scer\GAL4sca-P309
head bristle & socket | supernumerary | somatic clone
mechanosensory sensory organ & wing vein L1 & glial cell | supernumerary
mechanosensory sensory organ & wing vein L3 & glial cell | supernumerary
mesothoracic tergum & external sensory organ | conditional ts
microchaeta & antennal segment 3, with Scer\GAL4sca-P309
neuroblast | supernumerary & larval brain | somatic clone
peripheral nervous system & neuron
sensory neuron & abdominal segment 1
sensory neuron & abdominal segment 2
sensory neuron & abdominal segment 3
sensory neuron & abdominal segment 4
sensory neuron & abdominal segment 5
sensory neuron & abdominal segment 6
sensory neuron & abdominal segment 7
sensory neuron & abdominal segment 8
sensory neuron & abdominal segment 9
sensory neuron & abdominal segment 10
sensory neuron & abdominal segment 11
sensory neuron & mesothoracic segment
sensory neuron & metathoracic segment
sensory neuron & prothoracic segment
serotonin neuron & embryonic abdominal segment 8
Orthologs
Human Orthologs (via DIOPT v9.1)
Species\Gene Symbol
Score
Best Score
Best Reverse Score
Alignment
Complementation?
Transgene?
Homo sapiens (Human) (28)
11 of 14
Yes
Yes
 
4  
10 of 14
No
Yes
2 of 14
No
No
2 of 14
No
No
1  
2 of 14
No
No
2 of 14
No
Yes
2 of 14
No
No
2 of 14
No
No
2 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1  
1 of 14
No
No
1 of 14
No
No
2  
1 of 14
No
No
1 of 14
No
Yes
1  
1 of 14
No
Yes
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1  
Hsap\LOC112267931
1 of 14
No
Yes
1 of 14
No
No
1 of 14
No
No
1  
1 of 14
No
No
1  
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1  
1 of 14
No
No
Model Organism Orthologs (via DIOPT v9.1)
Species\Gene Symbol
Score
Best Score
Best Reverse Score
Alignment
Complementation?
Transgene?
Rattus norvegicus (Norway rat) (25)
11 of 14
Yes
Yes
10 of 14
No
Yes
2 of 14
No
No
2 of 14
No
No
2 of 14
No
No
2 of 14
No
No
2 of 14
No
No
2 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
Yes
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
Mus musculus (laboratory mouse) (24)
11 of 14
Yes
Yes
9 of 14
No
Yes
 
1  
2 of 14
No
No
1  
2 of 14
No
No
2 of 14
No
No
2 of 14
No
No
2 of 14
No
No
1  
2 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
Xenopus tropicalis (Western clawed frog) (19)
6 of 13
Yes
Yes
6 of 13
Yes
Yes
1 of 13
No
No
1 of 13
No
No
1 of 13
No
No
1 of 13
No
No
1 of 13
No
No
1 of 13
No
Yes
1 of 13
No
No
1 of 13
No
Yes
1 of 13
No
No
1 of 13
No
Yes
1 of 13
No
No
1 of 13
No
No
1 of 13
No
No
1 of 13
No
No
1 of 13
No
No
1 of 13
No
No
1 of 13
No
No
Danio rerio (Zebrafish) (33)
11 of 14
Yes
Yes
11 of 14
Yes
Yes
2 of 14
No
No
2 of 14
No
No
2 of 14
No
No
2 of 14
No
No
2 of 14
No
Yes
2 of 14
No
Yes
2 of 14
No
No
2 of 14
No
No
2 of 14
No
No
2 of 14
No
Yes
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
Yes
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
Caenorhabditis elegans (Nematode, roundworm) (8)
11 of 14
Yes
Yes
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
No
1 of 14
No
Yes
1 of 14
No
No
1 of 14
No
No
Anopheles gambiae (African malaria mosquito) (12)
6 of 12
Yes
Yes
Arabidopsis thaliana (thale-cress) (0)
Saccharomyces cerevisiae (Brewer's yeast) (0)
Schizosaccharomyces pombe (Fission yeast) (0)
Escherichia coli (enterobacterium) (0)
Other Organism Orthologs (via OrthoDB)
Data provided directly from OrthoDB:numb. Refer to their site for version information.
Paralogs
Paralogs (via DIOPT v9.1)
Drosophila melanogaster (Fruit fly) (11)
3 of 13
3 of 13
3 of 13
3 of 13
3 of 13
2 of 13
1 of 13
1 of 13
1 of 13
1 of 13
1 of 13
Human Disease Associations
FlyBase Human Disease Model Reports
Disease Ontology (DO) Annotations
Models Based on Experimental Evidence ( 1 )
Allele
Disease
Evidence
References
Potential Models Based on Orthology ( 0 )
Human Ortholog
Disease
Evidence
References
Modifiers Based on Experimental Evidence ( 1 )
Allele
Disease
Interaction
References
Disease Associations of Human Orthologs (via DIOPT v9.1 and OMIM)
Note that ortholog calls supported by only 1 or 2 algorithms (DIOPT score < 3) are not shown.
Homo sapiens (Human)
Gene name
Score
OMIM
OMIM Phenotype
DO term
Complementation?
Transgene?
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.
Dmel gene
Ortholog showing functional complementation
Supporting References
Interactions
Summary of Physical Interactions
Interaction Browsers

Please see the Physical Interaction reports below for full details
protein-protein
Physical Interaction
Assay
References
RNA-RNA
Physical Interaction
Assay
References
Summary of Genetic Interactions
Interaction Browsers

Please look at the allele data for full details of the genetic interactions
Starting gene(s)
Interaction type
Interacting gene(s)
Reference
Starting gene(s)
Interaction type
Interacting gene(s)
Reference
External Data
Subunit Structure (UniProtKB)
Interacts with Nak.
(UniProt, P16554 )
Linkouts
BioGRID - A database of protein and genetic interactions.
DroID - A comprehensive database of gene and protein interactions.
MIST (genetic) - An integrated Molecular Interaction Database
MIST (protein-protein) - An integrated Molecular Interaction Database
Pathways
Signaling Pathways (FlyBase)
Metabolic Pathways
FlyBase
External Links
External Data
Linkouts
KEGG Pathways - A collection of manually drawn pathway maps representing knowledge of molecular interaction, reaction and relation networks.
SignaLink - A signaling pathway resource with multi-layered regulatory networks.
Class of Gene
Genomic Location and Detailed Mapping Data
Chromosome (arm)
2L
Recombination map
2-35
Cytogenetic map
Sequence location
FlyBase Computed Cytological Location
Cytogenetic map
Evidence for location
30B3-30B5
Limits computationally determined from genome sequence between P{PZ}scat1&P{PZ}numb03235 and P{EP}Oatp30BEP890
Experimentally Determined Cytological Location
Cytogenetic map
Notes
References
30B1-30B12
(determined by in situ hybridisation)
30B5-30B6
(determined by in situ hybridisation)
30B-30B
(determined by in situ hybridisation)
Experimentally Determined Recombination Data
Location
Left of (cM)
Right of (cM)
Notes
Stocks and Reagents
Stocks (27)
Genomic Clones (29)
cDNA Clones (89)
 

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 JBrowse for alignment of the cDNAs and ESTs to the gene model.

cDNA clones, fully sequenced
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)
RNAi and Array Information
Linkouts
DRSC - Results frm RNAi screens
Antibody Information
Laboratory Generated Antibodies
Commercially Available Antibodies
 
Cell Line Information
Publicly Available Cell Lines
 
    Other Stable Cell Lines
     
      Other Comments

      The numb product regulates the spdo protein localization.

      mol and numb proteins are colocalised at the plasma membrane in Schneider 2 cells. Inhibition of mol expression in Schneider 2 cells by RNA interference releases numb protein from the plasma membrane to the cytosol.

      l(2)gl acts together with numb in N inhibition and cell fate specification in the adult sensory organ precursor lineage.

      numb inhibits membrane localisation of spdo protein.

      numb is necessary and sufficient to prevent apoptosis in the abdominal ventral multidendritic neuron 1a lineage.

      The abdominal ventral multidendritic neuron 1a is generated by an asymetric divisions in which the numb gene product segregates to the neuron and the other daughter cell dies by apoptosis.

      numb is required for correct allocation of cell fate between the Malpighian tubule tip cell and its sibling.

      numb and spdo mediate the asymmetric divisions in the developing heart which result in the production of an odd-expressing pericardial cell and a cardioblast.

      numb functions downstream of cell division genes (CycA, Rca1 and stg) and progression through the cell cycle is required for asymmetric localisation of numb gene product and thus N mediated specification of the sib fate in the RP2/sib division.

      Asymmetrical segregation of numb protein into one of the sibling cells produced by division of muscle progenitor cells depends on insc, and is essential for the specification of distinct sibling cell fates.

      spdo and N act in opposition to numb to distinguish sibling neuron fates in the CNS.

      Changing the dose of maternal numb product directly affects CNS development and suggests that numb may have earlier CNS functions in addition to sibling neuron specification. The numb mutant phenotype is extremely sensitive to the dosage of spdo.

      The phosphotyrosine-binding (PTB) domain of numb is required for its function, but this domain is probably not involved in phosphotyrosine- dependent interactions.

      Asymmetric localisation, but not membrane localisation, of numb is inhibited by latrunculin A, an inhibitor of actin assembly. Deletion of either the first 41 amino acids or amino acids 41-118 of numb eliminates both localisation to the cell membrane and asymmetric localisation during mitosis, whereas C terminal deletions or deletion of central portions do not affect numb subcellular localisation. The first 227 amino acids of numb are sufficient for asymmetric localisation.

      numb PTB domain possesses a unique binding specificity that is distinct from the motifs recognised by other known PTB domains.

      The asymmetric distribution of numb protein in muscle progenitors and its asymmetric segregation between sibling cells as each progenitor divides underlies the segregation of cell fates in the myogenic lineages of the Drosophila embryo.

      numb is required to produce all es and md neurons, including the 'solo' md ones. numb is required for the acquisition or expression of the neuronal fate even in the absence of cell division.

      Analysis of the mutant phenotype reveals numb functions in the neuron/sheath cell lineage. numb forms a crescent in the dividing IIa and IIb cells suggesting that asymmetric localisation of numb is important for the cell fate determination in all three asymmetric cell divisions in the sensory organ lineage. Su(H) is required for only a subset of the asymmetric divisions that depend on the function of numb and N. Su(H) appears to act downstream of numb in the same genetic pathway in determining the fates of the IIa daughter cells, the hair cell and the socket cell, and Su(H) is negatively regulated by numb.

      Overexpression of numb in N mutants demonstrates a synergistic interaction suggesting that numb and N function in the same genetic pathway.

      Yeast two-hybrid interaction assay demonstrates a direct protein-protein interaction between N and numb.

      Orientation of the mitotic spindle and correct localisation of numb and pros in basal daughter cells requires insc.

      numb is not required to specify dMP2 fate, but dMP2 fate is due to lack of productive Dl-N signaling. The function of numb is to antagonise the Dl-N signal specifying vMP2 fate.

      A PID, phosphotyrosine interaction domain, has been found in the numb protein. PID is a protein protein interaction motif that binds to the Asn-Pro-X-Tyr(P) motif found in many tyrosine phosphorylated proteins.

      numb is required for the proper differentiation of md neurons.

      Loss of ttk or numb function in sensory organ precursor daughter cells results in reciprocal cell fate transformation, epistatic studies suggest that ttk acts downstream of numb.

      pros translocates to the membrane at the beginning of cell division and colocalises with numb throughout mitosis, suggesting a common mechanism for asymmetric segregation. numb and pros localisation is coupled to mitosis and tightly correlated with the position of one of the two centrosomes but independent of microtubules and actin.

      numb protein is necessary and sufficient to specify autonomously the dMP2 fate in the MP2 lineage.

      The numb product is a membrane associated protein that localizes asymmetrically to one half of the predivisional sensory organ precursor cell. Upon division the numb product segregates preferentially to one of the two daughter cells, which acquire distinct identities.

      Analysis of numb mutant embryos determines that growth cones can distinguish between individual muscle fibres during synaptogenesis. Growth cones retain their target preference even when the numbers and patterns of muscle fibres are altered.

      In mutants, the precursors of neurons and glial cells in the external sensory (es) organs are, for the most part, transformed into nonneural support cells; some of the es organs are duplicated. Transformation of neuron precursors into nonneural cells also occurs in the chordotonal (ch) organs. Precursors of the multiple dendrite (md) neurons undergo similar changes. Muscle development is abnormal; some muscles are fewer in number than in wild type and show pattern changes.

      The numb gene must be able to function in the embryo in order for the peripheral sensory neurons to acquire their correct identity.

      numb gene product is required for the process of cell identity establishment, mutations of numb remove peripheral sense organs.

      Relationship to Other Genes
      Source for database merge of

      Source for merge of: numb l(2)03235

      Additional comments
      Nomenclature History
      Source for database identify of
      Nomenclature comments
      Etymology
      Synonyms and Secondary IDs (14)
      Reported As
      Symbol Synonym
      Numb
      (Plygawko et al., 2025, Pinot and Le Borgne, 2024, Deng and Wang, 2022, Bellec et al., 2021, Boukhatmi, 2021, Gong et al., 2021, Houssin et al., 2021, Kump et al., 2021, Zhang et al., 2021, Bahrampour and Thor, 2020, Cui et al., 2020, Gaziova et al., 2020, Liu et al., 2020, Loyer and Januschke, 2020, Wen, 2020, Yaghmaeian Salmani and Thor, 2020, Hannaford et al., 2019, Ng et al., 2019, Alfred and Vaccari, 2018, Bellec et al., 2018, Carmena, 2018, Salazar and Yamamoto, 2018, Stephens et al., 2018, An et al., 2017, Basu et al., 2017, Wu et al., 2017, Xu et al., 2017, Yasugi and Nishimura, 2016, Zhang et al., 2016, Bajaj et al., 2015, Wang et al., 2015, Charng et al., 2014, Cheruiyot et al., 2014, Eroglu et al., 2014, Montagne and Gonzalez-Gaitan, 2014, Bergstralh et al., 2013, Chai et al., 2013, Chen et al., 2013, Culurgioni and Mapelli, 2013, Goh et al., 2013, Noatynska et al., 2013, Sato et al., 2013, Zhan et al., 2013, Giagtzoglou et al., 2012, Homem and Knoblich, 2012, Kelsom and Lu, 2012, Saini and Reichert, 2012, Siddall et al., 2012, Benhra et al., 2011, Nance and Zallen, 2011, Wang et al., 2011, Kitajima et al., 2010, Mudiganti et al., 2010, Sawa, 2010, Andrews et al., 2009, Coumailleau et al., 2009, Sousa-Nunes et al., 2009, Wang et al., 2009, Benetka et al., 2008, Chen et al., 2008, Perdigoto et al., 2008, Andersen et al., 2007, Kawahashi et al., 2007, Slack et al., 2007, Smith et al., 2007, Sommer et al., 2007, Speicher et al., 2007, Thomas and van Meyel, 2007, Wang et al., 2007, Wirtz-Peitz et al., 2007, Bowman et al., 2006, Chin and Yeston, 2006, Morrison and Kimble, 2006, Polo and Di, 2006, Siddall et al., 2006, Wang et al., 2006, David et al., 2005, Jafar-Nejad et al., 2005, Yamashita et al., 2005, Blagden and Glover, 2003, O'Connor-Giles and Skeath, 2003, Folberg-Blum et al., 2002, Schaefer et al., 2001, Berdnik et al., 2000, Zwahlen et al., 2000, Li et al., 1998, Weinmaster, 1997)
      l(2)s2201
      numb
      (Bandyadka et al., 2025, Leclercq and Maurange, 2025, Ma et al., 2024, Stewart et al., 2024, Wu et al., 2024, Zhang et al., 2024, Rajan et al., 2023, Titus et al., 2023, Wu et al., 2023, National Institute of Genetics Fly Stocks, 2022-, Papagiannouli, 2022, Rahman et al., 2022, Connacher and Goldstrohm, 2021, Girard et al., 2021, Michki et al., 2021, Pang et al., 2021, Cho et al., 2020, Cohen et al., 2020, Díaz-de-la-Peña et al., 2020, Feuillette et al., 2020, Li and Hidalgo, 2020, Medina-Yáñez et al., 2020, Shen and Sun, 2020, Domingos et al., 2019, Hall et al., 2019, Hope et al., 2019, Khan et al., 2019, Liu et al., 2019, Kahsai and Cook, 2018, Komori et al., 2018, Li et al., 2018, Schwarz et al., 2018, Franz et al., 2017, Li et al., 2017, Lin et al., 2017, Sallé et al., 2017, Trylinski et al., 2017, Wu et al., 2017, Chen et al., 2016, Dubois et al., 2016, Johnson et al., 2016, Sarov et al., 2016, Aradhya et al., 2015, Derivery et al., 2015, Kallsen et al., 2015, Keder et al., 2015, Weng and Cohen, 2015, Couturier et al., 2014, Janssens et al., 2014, Lacin et al., 2014, Lin et al., 2014, Montgomery et al., 2014, Cotton et al., 2013, Couturier et al., 2013, Jauffred et al., 2013, Weavers and Skaer, 2013, Webber et al., 2013, Zhou and Luo, 2013, Ahmad et al., 2012, Andersen et al., 2012, Berger et al., 2012, Couturier et al., 2012, Haenfler et al., 2012, Peng et al., 2012, Saini and Reichert, 2012, Ulvklo et al., 2012, Xiao et al., 2012, Duan et al., 2011, Endo et al., 2011, Furman and Bukharina, 2011, Neumüller et al., 2011, Ouyang et al., 2011, Ouyang et al., 2011, Rebeiz et al., 2011, Slattery et al., 2011, Toku et al., 2011, Wang et al., 2011, Bardin et al., 2010, Chang et al., 2010, Herz et al., 2010, Lin et al., 2010, Monastirioti et al., 2010, Xie et al., 2010, Ayroles et al., 2009, Babaoglan et al., 2009, Krejcí et al., 2009, Lacin et al., 2009, Liu et al., 2009, Mummery-Widmer et al., 2009, Roegiers et al., 2009, Simon et al., 2009, Southall and Brand, 2009, Anaka et al., 2008, Babaoglan et al., 2008, Gilchrist et al., 2008, Reed et al., 2008, Remaud et al., 2008, Rogulja-Ortmann et al., 2008, Tögel et al., 2008, Tran and Doe, 2008, Wheeler et al., 2008, Wirtz-Peitz et al., 2008, Wirtz-Peitz et al., 2008, Edenfeld et al., 2007, Gregory et al., 2007, Griffiths et al., 2007, Kankel et al., 2007, Korolchuk et al., 2007, Lee and Lundell, 2007, Maisonhaute et al., 2007, Wheeler and Crews, 2007, Zeitlinger et al., 2007, Zeitouni et al., 2007, Gallagher and Knoblich, 2006, Lee et al., 2006, Wang et al., 2006, Caussinus and Gonzalez, 2005, Clevers, 2005, Emery et al., 2005, Harbison et al., 2005, Hutterer and Knoblich, 2005, Karcavich and Doe, 2005, Macdonald and Long, 2005, Roegiers et al., 2005, Tang et al., 2005, Raymond et al., 2004, Rath et al., 2002, Dawes-Hoang and Wieschaus, 2001, Nagel et al., 2000)
      Secondary FlyBase IDs
      • FBgn0010532
      • FBgn0010684
      Datasets (0)
      Study focus (0)
      Experimental Role
      Project
      Project Type
      Title
      Study result (0)
      Result
      Result Type
      Title
      External Crossreferences and Linkouts ( 86 )
      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 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/GCRP - The gene-centric reference proteome (GCRP) provides a 1:1 mapping between genes and UniProt accessions in which a single 'canonical' isoform represents the product(s) of each protein-coding gene.
      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
      AlphaFold DB - AlphaFold provides open access to protein structure predictions for the human proteome and other key proteins of interest, to accelerate scientific research.
      BDGP expression data - Patterns of gene expression in Drosophila embryogenesis
      DRscDB - A single-cell RNA-seq resource for data mining and data comparison across species
      EMBL-EBI Single Cell Expression Atlas - Single cell expression across species
      FlyAtlas2 - A Drosophila melanogaster expression atlas with RNA-Seq, miRNA-Seq and sex-specific data
      FlyMine - An integrated database for Drosophila genomics
      InterPro - A database of protein families, domains and functional sites
      KEGG Genes - Molecular building blocks of life in the genomic space.
      MARRVEL_MODEL - MARRVEL (model organism gene)
      PDB - An information portal to biological macromolecular structures
      Linkouts
      BioGRID - A database of protein and genetic interactions.
      Drosophila Genomics Resource Center - Drosophila Genomics Resource Center (DGRC) cDNA clones
      DroID - A comprehensive database of gene and protein interactions.
      DRSC - Results frm RNAi screens
      Eukaryotic Promoter Database - A collection of databases of experimentally validated promoters for selected model organisms.
      FlyAtlas - Adult expression by tissue, using Affymetrix Dros2 array
      FlyCyc Genes - Genes from a BioCyc PGDB for Dmel
      Fly-FISH - A database of Drosophila embryo and larvae mRNA localization patterns
      Flygut - An atlas of the Drosophila adult midgut
      FlyMet - A comprehensive tissue-specific metabolomics resource for Drosophila.
      iBeetle-Base - RNAi phenotypes in the red flour beetle (Tribolium castaneum)
      Interactive Fly - A cyberspace guide to Drosophila development and metazoan evolution
      KEGG Pathways - A collection of manually drawn pathway maps representing knowledge of molecular interaction, reaction and relation networks.
      MIST (genetic) - An integrated Molecular Interaction Database
      MIST (protein-protein) - An integrated Molecular Interaction Database
      SignaLink - A signaling pathway resource with multi-layered regulatory networks.
      References (684)