FB2025_05 , released December 11, 2025
Gene: Dmel\kuk
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General Information
Symbol
Dmel\kuk
Species
D. melanogaster
Name
kugelkern
Annotation Symbol
CG5175
Feature Type
protein_coding_gene
FlyBase ID
FBgn0038476
Gene Model Status
Current
Stock Availability
9 publicly available
Gene Summary
kugelkern (kuk) encodes a nuclear envelope protein required for nuclear elongation during cellularization. It shares structural and functional similarities to lamins. [Date last reviewed: 2018-11-15] (FlyBase Gene Snapshot)
All Summaries
Key Links
Genomic Location
Cytogenetic map
89E12-89E12
Sequence location
Recombination map
3-59
RefSeq locus
NT_033777 REGION:17080244..17084781
Sequence
Get Decorated FASTA
Genomic Maps
Other Genome Views
The following external sites may use different assemblies or annotations than FlyBase.
NCBI
UCSC
Ensembl
PopFly
Function
Gene Ontology (GO) Annotations (4 terms)
Molecular Function (0 terms)
Terms Based on Experimental Evidence (0 terms)
Terms Based on Predictions or Assertions (0 terms)
Biological Process (3 terms)
Terms Based on Experimental Evidence (3 terms)
CV Term
Evidence
References
involved_in cellularization
inferred from mutant phenotype
(Pilot et al., 2006)
involved_in morphogenesis of embryonic epithelium
inferred from mutant phenotype
(Pilot et al., 2006)
involved_in nucleus organization
inferred from mutant phenotype
(Pilot et al., 2006)
Terms Based on Predictions or Assertions (0 terms)
Cellular Component (1 term)
Terms Based on Experimental Evidence (1 term)
CV Term
Evidence
References
located_in nuclear inner membrane
inferred from direct assay
(Pilot et al., 2006)
Terms Based on Predictions or Assertions (0 terms)
Gene Group (FlyBase)
Protein Family (UniProt)
-
Protein Signatures (InterPro)
    -
    Summaries
    Gene Snapshot
    kugelkern (kuk) encodes a nuclear envelope protein required for nuclear elongation during cellularization. It shares structural and functional similarities to lamins. [Date last reviewed: 2018-11-15]
    Gene Model and Products
    Number of Transcripts
    3
    Number of Unique Polypeptides
    1

    Please see the JBrowse view of Dmel\kuk 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 Q8SX89)

    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
    Comments on Gene Model

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

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

    Gene model reviewed during 5.49

    Transcript Data
    Annotated Transcripts
    Name
    FlyBase ID
    RefSeq ID
    Length (nt)
    Assoc. CDS (aa)
    kuk-RA
    FBtr0083397
    NM_142338
    2231
    570
    kuk-RB
    FBtr0083398
    NM_169745
    2238
    570
    kuk-RC
    FBtr0305987
    NM_001260219
    2200
    570
    Additional Transcript Data and Comments
    Reported size (kB)
    Comments
    External Data
    Crossreferences
    Polypeptide Data
    Annotated Polypeptides
    Name
    FlyBase ID
    Predicted MW (kDa)
    Length (aa)
    Theoretical pI
    UniProt
    RefSeq ID
    GenBank
    kuk-PA
    FBpp0082838
    60.2
    570
    5.11
    Q8SX89
    NP_650595
    AAN13733
    kuk-PB
    FBpp0082839
    60.2
    570
    5.11
    Q8SX89
    NP_732204
    AAF55387
    kuk-PC
    FBpp0297129
    60.2
    570
    5.11
    Q8SX89
    NP_001247148
    AFH06466
    Polypeptides with Identical Sequences

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

    570 aa isoforms: kuk-PA, kuk-PB, kuk-PC
    Additional Polypeptide Data and Comments
    Reported size (kDa)
    Comments
    External Data
    Crossreferences
    Linkouts
    Sequences Consistent with the Gene Model
    Nucleotide / Polypeptide Records
     
    UniProt
    Mapped Features

    Click to get a list of regulatory features (enhancers, TFBS, etc.) and gene disruptions (point mutations, indels, etc.) within or overlapping Dmel\kuk 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).

    -0.30

    Transcript Expression
    in situ
    Stage
    Tissue/Position (including subcellular localization)
    Reference
    embryonic stage
    epithelial cell

    Comment: clustered apical distribution

    (Lecuyer et al., 2007)
    epithelium
    (Lecuyer et al., 2007)
    embryonic stage 1 -- 3
    organism

    Comment: maternally deposited

    (Fisher et al., 2012)
    embryonic stage 1 -- 5
    epithelial cell
    (Lecuyer et al., 2007)
    epithelium
    (Lecuyer et al., 2007)
    embryonic stage 4 -- 6
    organism | intense | ubiquitous
    (Fisher et al., 2012)
    embryonic stage 7 -- 8
    antennal anlage

    Comment: reported as procephalic ectoderm anlage

    (Fisher et al., 2012)
    central brain anlage

    Comment: reported as procephalic ectoderm anlage

    (Fisher et al., 2012)
    dorsal head epidermis anlage

    Comment: reported as procephalic ectoderm anlage

    (Fisher et al., 2012)
    visual anlage

    Comment: reported as procephalic ectoderm anlage

    (Fisher et al., 2012)
    anterior endoderm anlage
    (Fisher et al., 2012)
    head mesoderm
    (Fisher et al., 2012)
    organism | intense | ubiquitous
    (Fisher et al., 2012)
    organism | ubiquitous
    (Fisher et al., 2012)
    trunk mesoderm
    (Fisher et al., 2012)
    ventral ectoderm
    (Fisher et al., 2012)
    embryonic stage 9 -- 10
    antennal primordium

    Comment: reported as procephalic ectoderm primordium

    (Fisher et al., 2012)
    central brain primordium

    Comment: reported as procephalic ectoderm primordium

    (Fisher et al., 2012)
    visual primordium

    Comment: reported as procephalic ectoderm primordium

    (Fisher et al., 2012)
    dorsal head epidermis primordium

    Comment: reported as procephalic ectoderm primordium

    (Fisher et al., 2012)
    lateral head epidermis primordium

    Comment: reported as procephalic ectoderm primordium

    (Fisher et al., 2012)
    ventral head epidermis primordium

    Comment: reported as procephalic ectoderm primordium

    (Fisher et al., 2012)
    organism | intense | ubiquitous
    (Fisher et al., 2012)
    organism | ubiquitous
    (Fisher et al., 2012)
    trunk mesoderm
    (Fisher et al., 2012)
    ventral nerve cord primordium
    (Fisher et al., 2012)
    embryonic stage 11 -- 12
    central brain primordium
    (Fisher et al., 2012)
    dorsal epidermis primordium
    (Fisher et al., 2012)
    embryonic central brain glial cell
    (Fisher et al., 2012)
    embryonic central brain neuron
    (Fisher et al., 2012)
    embryonic neuroblast of ventral nerve cord primordium
    (Fisher et al., 2012)
    larval lateral VNC glial cell
    (Fisher et al., 2012)
    lateral cord neuron
    (Fisher et al., 2012)
    organism | intense | ubiquitous
    (Fisher et al., 2012)
    organism | ubiquitous
    (Fisher et al., 2012)
    procephalic neuroblast
    (Fisher et al., 2012)
    tracheal primordium
    (Fisher et al., 2012)
    ventral nerve cord primordium
    (Fisher et al., 2012)
    embryonic stage 13 -- 16
    embryonic brain
    (Fisher et al., 2012)
    larval nervous system
    (Fisher et al., 2012)
    gonad
    (Fisher et al., 2012)
    sensory nervous system primordium
    (Fisher et al., 2012)
    larval ventral nerve cord
    (Fisher et al., 2012)
    lineage MNB primary interneuron
    (Kearney et al., 2004)
    larval MP1 neuron
    (Kearney et al., 2004)
    embryonic stage 15
    ventral nerve cord
    (Magalhaes et al., 2007)
    Additional Descriptive Data
    Marker for
     
    Subcellular Localization
    CV Term
    Polypeptide Expression
    immunolocalization
    Stage
    Tissue/Position (including subcellular localization)
    Reference
    embryonic stage 4
    epithelial cell
    (Lecuyer et al., 2007)
    mass spectroscopy
    Stage
    Tissue/Position (including subcellular localization)
    Reference
    adult stage
    adult head
    (Aradska et al., 2015)
    Additional Descriptive Data
    Marker for
     
    Subcellular Localization
    CV Term
    Evidence
    References
    located_in nuclear inner membrane
    inferred from direct assay
    (Pilot et al., 2006)
    Expression Deduced from Reporters
    High-Throughput Expression Data
    Associated Tools

    JBrowse - Visual display of RNA-Seq signals

    View Dmel\kuk in JBrowse
    RNA-Seq by Region - Search RNA-Seq expression levels by exon or genomic region
    Bulk Downloads
    RNA-Seq RPKM values for all genes
    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
    FlyBase Wiki
    Image Based Resources
    Alleles, Insertions, Transgenic Constructs, and Aberrations
    Classical and Insertion Alleles ( 3 )
    For All Classical and Insertion Alleles Show
     
    Other relevant insertions
    Transgenic Constructs ( 19 )
    For All Alleles Carried on Transgenic Constructs Show
    Transgenic constructs containing/affecting coding region of kuk
    Transgenic constructs containing regulatory region of kuk
    Aberrations (Deficiencies and Duplications) ( 4 )
    Inferred from experimentation ( 4 )
    Gene disrupted in
    Df(3R)CG5169-2
    (Brandt, 2006)
    Df(3R)Exel6176
    (Ryder, 2004.4.26)
    Df(3R)kuk15
    (Brandt, 2006)
    Df(3R)kuk24
    (Brandt, 2006)
    Inferred from location ( 4 )
    Variants
    Variant Molecular Consequences
    Alleles Representing Disease-Implicated Variants
    Phenotypes
    Orthologs
    Downloads
    Download All DIOPT Orthologs
    Human Orthologs (via DIOPT v9.1)
    Species\Gene Symbol
    Score
    Best Score
    Best Reverse Score
    Source
    Compara
    Domainoid
    eggNOG
    Hieranoid
    Homologene
    Inparanoid
    OMA
    OrthoDB
    OrthoFinder
    OrthoInspector
    orthoMCL
    Panther
    Phylome
    SonicParanoid
    Alignment
    Complementation?
    Transgene?
    Homo sapiens (Human) (0)
    Model Organism Orthologs (via DIOPT v9.1)
    Species\Gene Symbol
    Score
    Best Score
    Best Reverse Score
    Source
    Compara
    Domainoid
    eggNOG
    Hieranoid
    Homologene
    Inparanoid
    OMA
    OrthoDB
    OrthoFinder
    OrthoInspector
    orthoMCL
    Panther
    Phylome
    SonicParanoid
    Alignment
    Complementation?
    Transgene?
    Rattus norvegicus (Norway rat) (0)
    Mus musculus (laboratory mouse) (0)
    Xenopus tropicalis (Western clawed frog) (0)
    Danio rerio (Zebrafish) (0)
    Caenorhabditis elegans (Nematode, roundworm) (0)
    Anopheles gambiae (African malaria mosquito) (1)
    Agam\AgaP_AGAP003486
    5 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:kuk. Refer to their site for version information.
    Paralogs
    Downloads
    Download All DIOPT Paralogs
    Paralogs (via DIOPT v9.1)
    Human Disease Associations
    FlyBase Human Disease Model Reports
      Disease Ontology (DO) Annotations
      Models Based on Experimental Evidence ( 1 )
      Allele
      Disease
      Evidence
      References
      kukUASp.GFP
      model of  progeroid syndrome
      CEA
      (Brandt et al., 2023)
      Potential Models Based on Orthology ( 0 )
      Human Ortholog
      Disease
      Evidence
      References
      Modifiers Based on Experimental Evidence ( 0 )
      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.
      Interactions
      Summary of Physical Interactions
      Summary of Genetic Interactions
      Interaction Browsers
      Starting gene(s)
      Interaction type
      Interacting gene(s)
      Reference
      Starting gene(s)
      Interaction type
      Interacting gene(s)
      Reference
      External Data
      Linkouts
      BioGRID - A database of protein and genetic interactions.
      DroID - A comprehensive database of gene and protein interactions.
      MIST (protein-protein) - An integrated Molecular Interaction Database
      Pathways
      Signaling Pathways (FlyBase)
      Metabolic Pathways
      FlyBase
      External Links
      External Data
      Linkouts
      Class of Gene
      Genomic Location and Detailed Mapping Data
      Chromosome (arm)
      3R
      Recombination map
      3-59
      Cytogenetic map
      89E12-89E12
      Sequence location
      FlyBase Computed Cytological Location
      Cytogenetic map
      Evidence for location
      89E12-89E12
      Limits computationally determined from genome sequence between P{EP}CG5208EP562&P{EP}DadEP3196 and P{PZ}l(3)0788207882
      Experimentally Determined Cytological Location
      Cytogenetic map
      Notes
      References
      Experimentally Determined Recombination Data
      Location

      3-59

      (FlyBase, 2016)

      3-59.2

      (Comeron et al., 2012)
      Left of (cM)
      Right of (cM)
      Notes
      Stocks and Reagents
      Stocks (9)
      Genomic Clones (9)
       

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

      cDNA Clones (183)
       

      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)
      BDGP DGC clones
      Other clones
      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

          Farnesylation is required for proper nuclear localisation of the kuk product.

          (Pilot et al., 2006)

          In embryos injected with dsRNA made from templates generated with primers directed against this gene, nuclear morphology and subsequent epithelial organisation is defective. The nuclei elongate normally at the start of cellularisation but fail to maintain this shape and become rounded. This morphology change, together with a disruption of the centrosome-nuclear envelope interaction, cause the nuclei lose their regular apical anchoring and fall from the cortex. These nuclear defects perturb the regular columnar organisation of epithelial cells.

          (Pilot et al., 2006)

          In contrast to wild-type, in kuk deficient embryos, the nuclei remain short until the end of cellularization.

          (Großhans et al., 2005)
          Relationship to Other Genes
          Source for database merge of
          Additional comments
          Nomenclature History
          Source for database identify of

          Source for identity of: kuk CG5175

          (Großhans, 2005.9.6)
          Nomenclature comments
          Etymology

          kugelkern is German for `round kernel'.

          (Melcer and Gruenbaum, 2006)

          The name "charleston" refers to the phenotype seen during cellularisation in which nuclei perform an abnormal apicobasal 'dancing' movement.

          (Pilot et al., 2006)
          Synonyms and Secondary IDs (10)
          Datasets (0)
          Study focus (0)
          Experimental Role
          Project
          Project Type
          Title
          Study result (0)
          Result
          Result Type
          Title
          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/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/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
          KEGG Genes - Molecular building blocks of life in the genomic space.
          MARRVEL_MODEL - MARRVEL (model organism gene)
          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
          MIST (protein-protein) - An integrated Molecular Interaction Database
          References (71)