FB2026_01 , released March 12, 2026
FB2026_01 , released March 12, 2026
Gene: Dmel\Mocs3
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General Information
Symbol
Dmel\Mocs3
Species
D. melanogaster
Name
Molybdenum cofactor synthesis 3
Annotation Symbol
CG13090
Feature Type
FlyBase ID
FBgn0032054
Gene Model Status
Stock Availability
Enzyme Name (EC)
molybdopterin-synthase adenylyltransferase (2.7.7.80)
thiosulfate sulfurtransferase (2.8.1.1)
molybdopterin synthase sulfurtransferase (2.8.1.11)
Gene Summary
Molybdenum cofactor synthesis 3 (Mocs3) encodes a protein involved in molybdopterin cofactor synthesis and protein urmylation. [Date last reviewed: 2019-09-26] (FlyBase Gene Snapshot)
Also Known As

Uba4

Key Links
Genomic Location
Cytogenetic map
Sequence location
Recombination map
2-33
RefSeq locus
NT_033779 REGION:8517411..8519176
Sequence
Genomic Maps
Other Genome Views
The following external sites may use different assemblies or annotations than FlyBase.
Function
Gene Ontology (GO) Annotations (16 terms)
Molecular Function (8 terms)
Terms Based on Experimental Evidence (0 terms)
Terms Based on Predictions or Assertions (8 terms)
CV Term
Evidence
References
Biological Process (5 terms)
Terms Based on Experimental Evidence (2 terms)
CV Term
Evidence
References
inferred from mutant phenotype
involved_in protein urmylation
inferred from mutant phenotype
Terms Based on Predictions or Assertions (5 terms)
CV Term
Evidence
References
inferred from sequence or structural similarity with UniProtKB:O95396
inferred from sequence or structural similarity with UniProtKB:O95396
involved_in protein urmylation
inferred from biological aspect of ancestor with PANTHER:PTN000102537
inferred from sequence or structural similarity with UniProtKB:O95396
inferred from electronic annotation with InterPro:IPR028885
inferred from biological aspect of ancestor with PANTHER:PTN000102537
Cellular Component (3 terms)
Terms Based on Experimental Evidence (1 term)
CV Term
Evidence
References
is_active_in cytosol
inferred from direct assay
Terms Based on Predictions or Assertions (3 terms)
CV Term
Evidence
References
is_active_in cytoplasm
inferred from biological aspect of ancestor with PANTHER:PTN000102040
located_in cytosol
inferred from electronic annotation with InterPro:IPR028885
inferred from sequence or structural similarity with UniProtKB:O95396
inferred from sequence or structural similarity with UniProtKB:P12282
Protein Family (UniProt)
-
Catalytic Activity (EC/Rhea)
molybdopterin-synthase sulfurtransferase activity
[molybdopterin-synthase sulfur-carrier protein]-C-terminal Gly-Gly-AMP + S-sulfanyl-L-cysteinyl-[cysteine desulfurase] + AH2 = [molybdopterin- synthase sulfur-carrier protein]-C-terminal-Gly-aminoethanethioate + L-cysteinyl-[cysteine desulfurase] + A + AMP + 2 H(+) (2.8.1.11)
RHEA 48612: molybdopterin-synthase adenylyltransferase activity
[molybdopterin-synthase sulfur-carrier protein]-C-terminal Gly-Gly + ATP + H(+) = [molybdopterin-synthase sulfur-carrier protein]-C-terminal Gly-Gly-AMP + diphosphate (2.7.7.80)
RHEA 43616: thiosulfate-cyanide sulfurtransferase activity
thiosulfate + hydrogen cyanide = thiocyanate + sulfite + 2 H(+) (2.8.1.1)
RHEA 16881:
Summaries
Gene Snapshot
Molybdenum cofactor synthesis 3 (Mocs3) encodes a protein involved in molybdopterin cofactor synthesis and protein urmylation. [Date last reviewed: 2019-09-26]
Gene Group (FlyBase)
SULFURTRANSFERASES -
Sulfurtransferases catalyze the transfer of sulfur-containing groups.
URM1 ACTIVATING ENZYMES -
URM1 activating enzymes are 'non-canonical' E1 enzymes that form obligate homodimers and activate the ubiquitin-like protein URM1 for subsequent steps along its conjugation cascade. (Adapted from PMID:28234446.)
UNCLASSIFIED ADENYLYLTRANSFERASES -
This group comprises adenylyltransferases that do not classify under other groups in FlyBase.
Pathway (FlyBase)
Mo-MOLYBDOPTERIN COFACTOR BIOSYNTHESIS -
Mo-molybdopterin cofactor (Moco) biosynthesis begins in the mitochondrial matrix with the production of cyclic pyranopterin phosphate (cPMP). Following its transport into the cytosol, cPMP is converted into molybdopterin by the molybdopterin synthase complex. The molybdenum (Mo) atom is then inserted forming the Mo-molybdopterin cofactor (active Moco). Moco can be incorporated as such into proteins or it can be further modified by sulfation prior to its insertion into proteins. (Adapted from FBrf0238243.)
Protein Function (UniProtKB)
Plays a central role in 2-thiolation of mcm(5)S(2)U at tRNA wobble positions of cytosolic tRNA(Lys), tRNA(Glu) and tRNA(Gln) (By similarity). Also essential during biosynthesis of the molybdenum cofactor (PubMed:29491838). Acts by mediating the C-terminal thiocarboxylation of sulfur carriers URM1 and MOCS2A (PubMed:26715182). Its N-terminus first activates URM1 and MOCS2A as acyl-adenylates (-COAMP), then the persulfide sulfur on the catalytic cysteine is transferred to URM1 and MOCS2A to form thiocarboxylation (-COSH) of their C-terminus (By similarity). The reaction probably involves hydrogen sulfide that is generated from the persulfide intermediate and that acts as a nucleophile towards URM1 and MOCS2A (By similarity). Subsequently, a transient disulfide bond is formed (PubMed:26715182). Does not use thiosulfate as sulfur donor; NFS1 probably acting as a sulfur donor for thiocarboxylation reactions (By similarity).
(UniProt, Q9VLJ8)
Gene Model and Products
Number of Transcripts
3
Number of Unique Polypeptides
1

Please see the JBrowse view of Dmel\Mocs3 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 Q9VLJ8)

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 5.46

Transcript Data
Annotated Transcripts
Name
FlyBase ID
RefSeq ID
Length (nt)
Assoc. CDS (aa)
FBtr0079683
1684
453
FBtr0333413
1540
453
FBtr0333414
1687
453
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
FBpp0079295
50.2
453
5.73
Polypeptides with Identical Sequences

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

453 aa isoforms: Mocs3-PA, Mocs3-PB, Mocs3-PC
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\Mocs3 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).

3.81

Transcript Expression
Additional Descriptive Data
Marker for
 
Subcellular Localization
CV Term
Polypeptide Expression
Additional Descriptive Data
Marker for
 
Subcellular Localization
CV Term
Evidence
References
is_active_in cytosol
inferred from direct assay
Expression Deduced from Reporters
High-Throughput Expression Data
Associated Tools

JBrowse - Visual display of RNA-Seq signals

View Dmel\Mocs3 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 ( 5 )
For All Classical and Insertion Alleles Show
 
Other relevant insertions
Transgenic Constructs ( 8 )
For All Alleles Carried on Transgenic Constructs Show
Transgenic constructs containing/affecting coding region of Mocs3
Transgenic constructs containing regulatory region of Mocs3
Aberrations (Deficiencies and Duplications) ( 1 )
Inferred from experimentation ( 1 )
Inferred from location ( 7 )
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) (14)
14 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
No
2 of 14
No
No
18  
2 of 14
No
No
2 of 14
No
No
1  
1 of 14
No
No
1 of 14
No
Yes
1 of 14
No
No
1 of 14
No
No
1 of 14
No
Yes
Model Organism Orthologs (via DIOPT v9.1)
Species\Gene Symbol
Score
Best Score
Best Reverse Score
Alignment
Complementation?
Transgene?
Rattus norvegicus (Norway rat) (14)
14 of 14
Yes
Yes
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
Yes
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
Mus musculus (laboratory mouse) (15)
13 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
No
2 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
Yes
1 of 14
No
No
Xenopus tropicalis (Western clawed frog) (10)
11 of 13
Yes
Yes
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
Yes
1 of 13
No
No
1 of 13
No
No
1 of 13
No
Yes
Danio rerio (Zebrafish) (13)
13 of 14
Yes
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
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)
14 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
No
1 of 14
No
No
1 of 14
No
No
Anopheles gambiae (African malaria mosquito) (10)
12 of 12
Yes
Yes
Arabidopsis thaliana (thale-cress) (21)
13 of 13
Yes
Yes
2 of 13
No
No
2 of 13
No
No
2 of 13
No
No
2 of 13
No
No
2 of 13
No
No
2 of 13
No
No
2 of 13
No
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
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
1 of 13
No
No
1 of 13
No
No
Saccharomyces cerevisiae (Brewer's yeast) (11)
13 of 13
Yes
Yes
2 of 13
No
No
2 of 13
No
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
Yes
1 of 13
No
No
Schizosaccharomyces pombe (Fission yeast) (10)
12 of 12
Yes
Yes
2 of 12
No
No
2 of 12
No
No
2 of 12
No
No
1 of 12
No
No
1 of 12
No
No
1 of 12
No
Yes
1 of 12
No
No
1 of 12
No
Yes
1 of 12
No
No
Escherichia coli (enterobacterium) (8)
10 of 11
Yes
Yes
6 of 11
No
Yes
1 of 11
No
No
1 of 11
No
No
1 of 11
No
Yes
1 of 11
No
Yes
1 of 11
No
Yes
1 of 11
No
Yes
Other Organism Orthologs (via OrthoDB)
Data provided directly from OrthoDB:Mocs3. Refer to their site for version information.
Paralogs
Paralogs (via DIOPT v9.1)
Drosophila melanogaster (Fruit fly) (11)
4 of 13
4 of 13
4 of 13
4 of 13
4 of 13
4 of 13
4 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 ( 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
    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
    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
    External Links
    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
    2-33
    Cytogenetic map
    Sequence location
    FlyBase Computed Cytological Location
    Cytogenetic map
    Evidence for location
    29D4-29D4
    Limits computationally determined from genome sequence between P{lacW}l(2)k03706k03706&P{lacW}Acerk07704 and P{PZ}lmg03424
    Experimentally Determined Cytological Location
    Cytogenetic map
    Notes
    References
    Experimentally Determined Recombination Data
    Location
    Left of (cM)
    Right of (cM)
    Notes
    Stocks and Reagents
    Stocks (17)
    Genomic Clones (11)
     

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

    cDNA Clones (13)
     

    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
    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
        Relationship to Other Genes
        Source for database merge of
        Additional comments
        Nomenclature History
        Source for database identify of

        Source for identity of: Uba4 CG13090

        Source for identity of: Mocs3 Uba4

        Nomenclature comments

        FlyBase curator comment: Changed symbol from Uba4 to Mocs3 because this is clearly the ortholog of E.coli moeB and human MOCS3, as shown by Marelja et al. (2018).

        Etymology

        Named 'Uba4' after its homologues in other species.

        Synonyms and Secondary IDs (9)
        Datasets (0)
        Study focus (0)
        Experimental Role
        Project
        Project Type
        Title
        Study result (0)
        Result
        Result Type
        Title
        External Crossreferences and Linkouts ( 47 )
        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
        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
        FlyMet - A comprehensive tissue-specific metabolomics resource for Drosophila.
        iBeetle-Base - RNAi phenotypes in the red flour beetle (Tribolium castaneum)
        KEGG Pathways - A collection of manually drawn pathway maps representing knowledge of molecular interaction, reaction and relation networks.
        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 (35)