FB2025_01 , released February 20, 2025
Gene: Dmel\FASN1
Open Close
General Information
Symbol
Dmel\FASN1
Species
D. melanogaster
Name
Fatty acid synthase 1
Annotation Symbol
CG3523
Feature Type
FlyBase ID
FBgn0283427
Gene Model Status
Stock Availability
Enzyme Name (EC)
[acyl-carrier-protein] S-acetyltransferase (2.3.1.38)
beta-ketoacyl-[acyl-carrier-protein] synthase I (2.3.1.41)
fatty-acid synthase system (2.3.1.85)
Gene Summary
Fatty acid synthase 1 (FASN1) encodes a fatty acid synthase involved in glycogen metabolism and triglyceride biosynthesis. [Date last reviewed: 2019-09-12] (FlyBase Gene Snapshot)
Also Known As

FAS, fatty acid synthase, dFAS, FASN, BcDNA:GH07626

Key Links
Genomic Location
Cytogenetic map
Sequence location
Recombination map
2-8
RefSeq locus
NT_033779 REGION:3056598..3068177
Sequence
Genomic Maps
Other Genome Views
The following external sites may use different assemblies or annotations than FlyBase.
Function
Gene Ontology (GO) Annotations (15 terms)
Molecular Function (6 terms)
Terms Based on Experimental Evidence (2 terms)
CV Term
Evidence
References
inferred from high throughput direct assay
Terms Based on Predictions or Assertions (5 terms)
CV Term
Evidence
References
Biological Process (8 terms)
Terms Based on Experimental Evidence (6 terms)
CV Term
Evidence
References
inferred from direct assay
inferred from mutant phenotype
inferred from mutant phenotype
acts_upstream_of_positive_effect regulation of lipid storage
inferred from mutant phenotype
inferred from mutant phenotype
inferred from mutant phenotype
Terms Based on Predictions or Assertions (2 terms)
CV Term
Evidence
References
inferred from electronic annotation with InterPro:IPR001031
inferred from biological aspect of ancestor with PANTHER:PTN000196555
inferred from electronic annotation with InterPro:IPR018201
Cellular Component (1 term)
Terms Based on Experimental Evidence (0 terms)
Terms Based on Predictions or Assertions (1 term)
CV Term
Evidence
References
located_in cytosol
inferred from sequence or structural similarity with UniProtKB:P49327
Protein Family (UniProt)
-
Catalytic Activity (EC/Rhea)
3-oxoacyl-[acyl-carrier-protein] synthase activity
a fatty acyl-[ACP] + malonyl-[ACP] + H(+) = a 3-oxoacyl-[ACP] + holo- [ACP] + CO2 (2.3.1.41)
RHEA 22836: fatty acid synthase activity
acetyl-CoA + n malonyl-CoA + 2n NADPH + 2n H(+) = a long-chain fatty acid + (n+1) CoA + n CO2 + 2n NADP(+) (2.3.1.85)
RHEA 14993: [acyl-carrier-protein] S-acetyltransferase activity
holo-[ACP] + acetyl-CoA = acetyl-[ACP] + CoA (2.3.1.38)
RHEA 41788:
Summaries
Gene Snapshot
Fatty acid synthase 1 (FASN1) encodes a fatty acid synthase involved in glycogen metabolism and triglyceride biosynthesis. [Date last reviewed: 2019-09-12]
Gene Group (FlyBase)
FATTY ACID SYNTHASES -
Fatty acid elongation occurs in three cellular compartments: the cytosol, mitochondria, and endoplasmic reticulum (microsomes). In the cytosol, fatty acid elongation is part of de novo lipogenesis and involves acetyl-CoA carboxylase and fatty acid synthase. Fatty acid synthases utilize acetyl CoA and malonyl CoA to elongate fatty acids by two carbons. The primary end product of de novo lipogenesis is palmitate ( 16:0 ) and to a lesser extent myristate ( 14:0 ) and stearate ( 18:0 ). (Adapted from PMID:19763486.)
UNCLASSIFIED OXIDOREDUCTASES -
This group comprises oxidoreductases that do not classify under other groups in FlyBase.
Gene Model and Products
Number of Transcripts
2
Number of Unique Polypeptides
2

Please see the JBrowse view of Dmel\FASN1 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 B7Z001)

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 5.47

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

Transcript Data
Annotated Transcripts
Name
FlyBase ID
RefSeq ID
Length (nt)
Assoc. CDS (aa)
FBtr0077659
8622
2438
FBtr0335387
8417
2540
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
FBpp0077343
266.4
2438
6.31
FBpp0307371
278.0
2540
6.63
Polypeptides with Identical Sequences

None of the polypeptides share 100% sequence identity.

Additional Polypeptide Data and Comments
Reported size (kDa)
Comments
External Data
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\FASN1 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).

-0.79

Transcript Expression
in situ
Stage
Tissue/Position (including subcellular localization)
Reference
RT-PCR
Stage
Tissue/Position (including subcellular localization)
Reference
Additional Descriptive Data

FASN1 expression is detected in both internal organs and leftover carcass by RT-qPCR.

Marker for
Subcellular Localization
CV Term
Polypeptide Expression
mass spectroscopy
Stage
Tissue/Position (including subcellular localization)
Reference
Additional Descriptive Data
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\FASN1 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
Images
Alleles, Insertions, Transgenic Constructs, and Aberrations
Classical and Insertion Alleles ( 16 )
For All Classical and Insertion Alleles Show
 
Other relevant insertions
Transgenic Constructs ( 9 )
For All Alleles Carried on Transgenic Constructs Show
Transgenic constructs containing/affecting coding region of FASN1
Transgenic constructs containing regulatory region of FASN1
Aberrations (Deficiencies and Duplications) ( 3 )
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
Orthologs
Human Orthologs (via DIOPT v9.1)
Species\Gene Symbol
Score
Best Score
Best Reverse Score
Alignment
Complementation?
Transgene?
Homo sapiens (Human) (19)
12 of 14
Yes
No
Hsap\LINC00614
2 of 14
No
Yes
1 of 14
No
No
1  
1 of 14
No
No
1 of 14
No
No
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
4  
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  
1 of 14
No
No
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) (8)
12 of 14
Yes
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) (7)
11 of 14
Yes
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) (13)
6 of 13
Yes
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
Yes
1 of 13
No
Yes
1 of 13
No
No
1 of 13
No
No
1 of 13
No
Yes
1 of 13
No
No
1 of 13
No
No
Danio rerio (Zebrafish) (10)
12 of 14
Yes
Yes
11 of 14
No
Yes
4 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
Caenorhabditis elegans (Nematode, roundworm) (14)
12 of 14
Yes
No
3 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
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
Anopheles gambiae (African malaria mosquito) (15)
11 of 12
Yes
Yes
Arabidopsis thaliana (thale-cress) (26)
3 of 13
Yes
No
2 of 13
No
No
2 of 13
No
No
2 of 13
No
No
2 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
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
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
1 of 13
No
No
Saccharomyces cerevisiae (Brewer's yeast) (13)
1 of 13
Yes
No
1 of 13
Yes
No
1 of 13
Yes
No
1 of 13
Yes
No
1 of 13
Yes
No
1 of 13
Yes
No
1 of 13
Yes
No
1 of 13
Yes
No
1 of 13
Yes
No
1 of 13
Yes
No
1 of 13
Yes
No
1 of 13
Yes
No
1 of 13
Yes
No
Schizosaccharomyces pombe (Fission yeast) (4)
3 of 12
Yes
No
2 of 12
No
No
1 of 12
No
No
1 of 12
No
No
Escherichia coli (enterobacterium) (3)
1 of 11
Yes
No
1 of 11
Yes
No
1 of 11
Yes
No
Other Organism Orthologs (via OrthoDB)
Data provided directly from OrthoDB:FASN1. Refer to their site for version information.
Paralogs
Paralogs (via DIOPT v9.1)
Drosophila melanogaster (Fruit fly) (6)
11 of 13
7 of 13
2 of 13
2 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 ( 0 )
    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.
    Interactions
    Summary of Physical Interactions
    esyN Network Diagram
    Show neighbor-neighbor interactions:
    Show/hide secondary interactors 
    (data from AllianceMine provided by esyN)
    Select Layout:
    Legend:
    Protein
    RNA
    Selected Interactor(s)
    Other Interaction Browsers

    Please see the Physical Interaction reports below for full details
    protein-protein
    Physical Interaction
    Assay
    References
    RNA-protein
    Physical Interaction
    Assay
    References
    Summary of Genetic Interactions
    esyN Network Diagram
    Show/hide secondary interactors 
    (data from AllianceMine provided by esyN)
    esyN Network Key:
    Suppression
    Enhancement
    Other 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
    Linkouts
    MIST (genetic) - An integrated Molecular Interaction Database
    MIST (protein-protein) - An integrated Molecular Interaction Database
    Pathways
    Signaling Pathways (FlyBase)
    Metabolic Pathways
    FlyBase
    External Links
    KEGG Metabolic Pathways - A collection of manually drawn metabolic pathway maps representing knowledge of molecular interaction, reaction and relation networks.
    Reactome Metabolic Pathways - An open-source, open access, manually curated and peer-reviewed metabolic pathway database.
    External Data
    Linkouts
    KEGG Pathways - A collection of manually drawn pathway maps representing knowledge of molecular interaction, reaction and relation networks.
    Reactome - An open-source, open access, manually curated and peer-reviewed pathway database.
    Class of Gene
    Genomic Location and Detailed Mapping Data
    Chromosome (arm)
    2L
    Recombination map
    2-8
    Cytogenetic map
    Sequence location
    FlyBase Computed Cytological Location
    Cytogenetic map
    Evidence for location
    23C5-23D1
    Limits computationally determined from genome sequence between P{PZ}lilli00632 and P{PZ}toc01361
    Experimentally Determined Cytological Location
    Cytogenetic map
    Notes
    References
    Experimentally Determined Recombination Data
    Location
    Left of (cM)
    Right of (cM)
    Notes
    Stocks and Reagents
    Stocks (14)
    Genomic Clones (19)
     
    cDNA Clones (121)
     

    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
    Antibody Information
    Laboratory Generated Antibodies
     

    polyclonal

    Commercially Available Antibodies
     
    Cell Line Information
    Publicly Available Cell Lines
     
      Other Stable Cell Lines
       
        Other Comments

        Fatty acid synthase (FASN) is encoded by three distinct genes: CG3523, CG3524 and CG17374. Of these, CG3523 is the only FASN gene that is expressed in internal organs, has an essential function (outside of oenocytes), and whose expression affects total triacylglycerol levels in vivo.

        The gene referred to as "CG3525" in Table 2 of FBrf0201413 should have been referred to as "CG3523".

        Identified in an RNAi screen for host factors that alter infection of SL2 cells by M.fortuitum.

        Relationship to Other Genes
        Source for database merge of

        Source for merge of: BcDNA:GH07626 anon- EST:Posey235 anon- EST:Posey43

        Source for merge of: CG3523 anon-WO0138581.1

        Source for merge of: CG3523 Fas

        Additional comments

        Source for merge of CG3523 anon-WO0138581.1 was sequence comparison ( date:051113 ).

        There are 3 Fatty acid synthase genes in the Dmel genome (FBrf0219401, FBrf0224329): CG3523, CG3524 and CG17374. Through to the FB2015_01 release, there was also an unannotated gene called 'Fas' ('Fatty acid synthase', FBgn0022805), which had no biological data attached but did have 23 associated publications (published between 1990-2015). Of these 23 publications, 15 are actually specifically referring to the CG3523 gene; 2 do not specify which 'Fatty acid synthase' gene they are referring to; and 6 early papers (published 1990-1999) refer to a fatty acid synthase 'activity'. These latter 8 papers are likely assaying the CG3523 gene product as this is the major, ubiquitously expressed Fatty acid synthase of the three (see FBrf0219401, FBrf0224329, modENCODE RNA-Seq). Therefore, the unannotated 'Fas' gene has been merged with 'CG3523'.

        Nomenclature History
        Source for database identify of

        Source for identity of: FASN1 CG3523

        Nomenclature comments

        There are 3 Fatty acid synthase genes in the Dmel genome (FBrf0219401, FBrf0224329): CG3523 (aka FAS), CG3524 (aka mFAS) and CG17374. The CG3523 gene product is the major, ubiquitously expressed Fatty acid synthase of the three (and the most studied), while CG3524 and CG17374 have lower and more restricted expression (FBrf0219401, FBrf0224329; also see modENCODE RNAseq). The following systematic and informative symbols have therefore been adopted: CG3523 = 'FASN1', CG3524 = 'FASN2' and CG17374 = 'FASN3'. ('FASN', rather than 'FAS', has been used as a shared prefix as this more clearly distinguishes these 'Fatty acid synthase' genes from the unrelated 'faint sausage' gene (symbol 'fas') and 'Fasciclin' genes (symbols 'Fas1', 'Fas2' and 'Fas3'). Furthermore 'FASN' is the HGNC symbol for the human ortholog.)

        Etymology
        Synonyms and Secondary IDs (26)
        Reported As
        Symbol Synonym
        BcDNA:gh07626
        anon-EST:Posey235
        anon-EST:Posey43
        anon-WO0138581.1
        Secondary FlyBase IDs
        • FBgn0027571
        • FBgn0027682
        • FBgn0027719
        • FBgn0044793
        • FBgn0022805
        Datasets (0)
        Study focus (0)
        Experimental Role
        Project
        Project Type
        Title
        Study result (0)
        Result
        Result Type
        Title
        External Crossreferences and Linkouts ( 81 )
        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.
        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
        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
        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.
        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
        iBeetle-Base - RNAi phenotypes in the red flour beetle (Tribolium castaneum)
        KEGG Metabolic Pathways - A collection of manually drawn metabolic pathway maps representing knowledge of molecular interaction, reaction and relation networks.
        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
        Reactome - An open-source, open access, manually curated and peer-reviewed pathway database.
        Reactome Metabolic Pathways - An open-source, open access, manually curated and peer-reviewed metabolic pathway database.
        References (219)