FB2026_03 , released September 17, 2026
Gene: Dmel\nullo
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General Information
Symbol
Dmel\nullo
Species
D. melanogaster
Name
nullo
Annotation Symbol
CG14426
Feature Type
FlyBase ID
FBgn0004143
Gene Model Status
Stock Availability
Gene Summary
Actin-myosin network stability during cellularization. Might be involved in increasing actin-actin interactions or membrane-to-cytoskeleton attachments. nullo together with Sry-a and bnk may provide auxiliary functions, by acting both to stabilize a large and dynamic microfilament structure and regulate its functions. (UniProt, P32845)
Contribute a Gene Snapshot for this gene.
Key Links
Genomic Location
Cytogenetic map
Sequence location
Recombination map
1-19
RefSeq locus
NC_004354 REGION:7049476..7050321
Sequence
Other Genome Views
The following external sites may use different assemblies or annotations than FlyBase.
Function
Gene Ontology (GO) Annotations (7 terms)
Molecular Function (0 terms)
Terms Based on Experimental Evidence (0 terms)
Terms Based on Predictions or Assertions (0 terms)
Biological Process (5 terms)
Terms Based on Experimental Evidence (4 terms)
CV Term
Evidence
References
inferred from mutant phenotype
inferred from genetic interaction with FLYBASE:slam; FB:FBgn0043854
inferred from mutant phenotype
inferred from mutant phenotype
Terms Based on Predictions or Assertions (1 term)
CV Term
Evidence
References
involved_in cellularization
traceable author statement
Cellular Component (2 terms)
Terms Based on Experimental Evidence (0 terms)
Terms Based on Predictions or Assertions (2 terms)
CV Term
Evidence
References
traceable author statement
traceable author statement
Gene Group / Complex (FlyBase)
Protein Family (UniProt)
-
Protein Signatures (InterPro)
Summaries
Protein Function (UniProtKB)
Actin-myosin network stability during cellularization. Might be involved in increasing actin-actin interactions or membrane-to-cytoskeleton attachments. nullo together with Sry-a and bnk may provide auxiliary functions, by acting both to stabilize a large and dynamic microfilament structure and regulate its functions.
(UniProt, P32845)
Summary (Interactive Fly)

novel myristoylprotein with a cluster of basic amino acids present in the basal junction and required for its formation at the onset of cellularization

Gene Model and Products
Number of Transcripts
1
Number of Unique Polypeptides
1

Please see the JBrowse view of Dmel\nullo 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 P32845)

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

Gene model reviewed during 5.52

Transcript Data
Annotated Transcripts
Name
FlyBase ID
RefSeq ID
Length (nt)
Assoc. CDS (aa)
FBtr0299565
846
213
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
FBpp0288840
24.2
213
11.17
Polypeptides with Identical Sequences

There is only one protein coding transcript and one polypeptide associated with this gene

Additional Polypeptide Data and Comments
Reported size (kDa)

26.5, 25 (kD observed)

Comments
External Data
Crossreferences
InterPro - A database of protein families, domains and functional sites
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\nullo 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).

NA

Transcript Expression
No Assay Recorded
Stage
Tissue/Position (including subcellular localization)
Reference
in situ
Stage
Tissue/Position (including subcellular localization)
Reference
Additional Descriptive Data

nullo and bnk are zygotically transcribed and induced during the slow phase of cellularization. These transcripts rapidly disappear at the transition to the fast phase of cellularization.

nullo transcripts are first detected at embryonic cycle 11, peak during the mitosis separating cycles 13 and 14, and disappear rapidly at the beginning of cellularization. Expression occurs throughout the cortex of the embryo with less RNA accumulation at the poles than in the rest of the embryo. In cycle 14 broad bands of heavier accumulation are visible. Transcript levels in cycle 14 may be coupled to the nucleocytoplasmic ratio. nullo is not expressed at any other times in development. The onset of expression is not affected in Sry-α mutants and does not require any other zygotically acting genes.

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

nullo protein is blastoderm-specific and is detected between interphase of embryonic cycle 13 and the beginning of gastrulation, with highest levels in cycle 14 and during the slow phase of cellularization. nullo protein localizes between interphase actin caps and within metaphase furrows during cycle 13. At cycle 14, nullo protein co-localizes with the actin network in a punctate hexagonal pattern, and during the slow phase of cellularization continues to be associated with the plasma membrane at, and apical to, the invaginating furrow canal. During the fast phase, less protein is found at the furrow canal, and the majority of nullo protein is dispersed in the cytoplasm. Protein is not detected above background levels at the completion of cellularization.

Marker for
 
Subcellular Localization
CV Term
Evidence
References
Expression Deduced from Reporters
High-Throughput Expression Data
Associated Tools

JBrowse - Visual display of RNA-Seq signals

View Dmel\nullo 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
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
Alleles, Insertions, Transgenic Constructs, and Aberrations
Classical and Insertion Alleles ( 6 )
For All Classical and Insertion Alleles Show
 
Other relevant insertions
Transgenic Constructs ( 20 )
For All Alleles Carried on Transgenic Constructs Show
Transgenic constructs containing/affecting coding region of nullo
Transgenic constructs containing regulatory region of nullo
Aberrations (Deficiencies and Duplications) ( 19 )
Variants
Variant Molecular Consequences
Alleles Representing Disease-Implicated Variants
Phenotypes
Orthologs
Human Orthologs (via DIOPT v9.1)
Species\Gene Symbol
Score
Best Score
Best Reverse Score
Alignment
Complementation?
Transgene?
Homo sapiens (Human) (0)
Model Organism Orthologs (via DIOPT v9.1)
Species\Gene Symbol
Score
Best Score
Best Reverse Score
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) (0)
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:nullo. Refer to their site for version information.
Paralogs
Paralogs (via DIOPT v9.1)
Human Disease Associations
FlyBase Human Disease Model Reports
    Disease Ontology (DO) Annotations
    Models Based on Experimental Evidence ( 0 )
    Allele
    Disease
    Evidence
    References
    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
    Interaction Browsers
    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
    DroID - A comprehensive database of gene and protein interactions.
    Pathways
    Signaling Pathways (FlyBase)
    Metabolic Pathways
    FlyBase
    External Links
    External Data
    Linkouts
    Class of Gene
    Genomic Location and Detailed Mapping Data
    Chromosome (arm)
    X
    Recombination map
    1-19
    Cytogenetic map
    Sequence location
    FlyBase Computed Cytological Location
    Cytogenetic map
    Evidence for location
    6F1-6F1
    Limits computationally determined from genome sequence between P{EP}inx7EP1641 and P{EP}CG9650EP1340&P{EP}CG9650EP1617
    Experimentally Determined Cytological Location
    Cytogenetic map
    Notes
    References
    6F-6F
    (determined by in situ hybridisation)
    6F1-6F2
    (determined by in situ hybridisation)
    Experimentally Determined Recombination Data
    Location
    Left of (cM)
    Right of (cM)
    Notes
    Stocks and Reagents
    Stocks (7)
    Genomic Clones (25)
    cDNA Clones (4)
     

    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
         
        Developmental Studies Hybridoma Bank - Monoclonal antibodies for use in research
        Cell Line Information
        Publicly Available Cell Lines
         
          Other Stable Cell Lines
           
            Other Comments

            Together with slam, nullo is essential for specification of the cleavage furrow.

            dsRNA has been made from templates generated with primers directed against this gene.

            dsRNA made from templates generated with primers directed against this gene is tested in an RNAi screen for effects on actin-based lamella formation.

            nullo loss of function mutations cause defects in the formation and maintenance of the basal junction, but do not affect apical junction formation during cellularisation in the embryo.

            In a sample of 79 genes with multiple introns, 33 showed significant heterogeneity in G+C content among introns of the same gene and significant positive correspondence between the intron and the third codon position G+C content within genes. These results are consistent with selection adding against preferred codons at the start of genes.

            Introduction of Dvir\nullo into D.melanogaster nullo mutant embryos rescues the defects in the actin network and allows the development of viable adults.

            Two out of four conserved 7-13bp motifs found in the 5' promoter region of Sry-α, which is also involved in cellularization, are also found in the nullo gene 5' region.

            P element constructs carrying a 4.5kb fragment containing nullo+t4.5 were able to rescue the embryonic lethality associated with nullo mutations.

            The requirement for nullo function during development has been determined. Analysis of nullo mutant clones in adults reveals that nullo activity is not required for cell division in imaginal discs. Germline clone experiments suggest that maternal expression of nullo is not essential for either germline proliferation or the cellularisation of progeny.

            The nullo gene is required for the stability of the actin-myosin contractile network during cellularization.

            Relationship to Other Genes
            Source for database merge of

            Source for merge of: nullo BcDNA:RE47733

            Additional comments

            Source for merge of nullo BcDNA:RE47733 was a shared cDNA ( date:030728 ).

            Nomenclature History
            Source for database identify of
            Nomenclature comments
            Etymology
            Synonyms and Secondary IDs (4)
            Datasets (0)
            Study focus (0)
            Experimental Role
            Project
            Project Type
            Title
            Study result (0)
            Result
            Result Type
            Title
            External Crossreferences and Linkouts ( 29 )
            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/Swiss-Prot - Manually annotated and reviewed 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.
            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)
            Linkouts
            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
            Developmental Studies Hybridoma Bank - Monoclonal antibodies for use in research
            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
            Interactive Fly - A cyberspace guide to Drosophila development and metazoan evolution
            References (120)