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General Information
Symbol
Dmel\lab
Species
D. melanogaster
Name
labial
Annotation Symbol
CG1264
Feature Type
FlyBase ID
FBgn0002522
Gene Model Status
Stock Availability
Gene Snapshot
labial (lab) encodes the anterio-most expressed member of the Antennapedia complex (ANT-C), one of two Hox gene complexes. Members of the ANT-C control the identity of segments that contribute to the head and the anterior thorax. The product of lab specifies the identity of the intercalary segment and also functions in the development of copper cells in the midgut. [Date last reviewed: 2019-03-14]
Also Known As

F90-2, F24

Key Links
Genomic Location
Cytogenetic map
Sequence location
3R:6,661,427..6,678,590 [-]
Recombination map

3-48

RefSeq locus
NT_033777 REGION:6661427..6678590
Sequence
Other Genome Views
The following external sites may use different assemblies or annotations than FlyBase.
Function
GO Summary Ribbons
Protein Family (UniProt)
Belongs to the Antp homeobox family. Labial subfamily. (P10105)
Summaries
Gene Group (FlyBase)
ANTENNAPEDIA COMPLEX -
The Antennapedia complex (ANT-C) is one of two Hox gene complexes. Hox genes encode homeodomain transcription factors. ANT-C controls the identity of segments that contribute to the head and the anterior thorax. ANT-C homeotic genes show colinearity in their expression patterns with the exception of pb. (Adapted from FBrf0190304).
HOX-LIKE HOMEOBOX TRANSCRIPTION FACTORS -
HOX-like (HOXL) homeobox transcription factors are sequence-specific DNA binding proteins that regulate transcription. They encompass transcription factors encoded by the Hox genes of the Antennapedia and the Bithorax gene complexes and genes closely related in sequence. HOXL transcription factors are major regulators of animal development. (Adapted from FBrf0232555).
Protein Function (UniProtKB)
Sequence-specific transcription factor which is part of a developmental regulatory system that provides cells with specific positional identities on the anterior-posterior axis. Required for proper head development.
(UniProt, P10105)
Phenotypic Description (Red Book; Lindsley and Zimm 1992)
lab: labial
Null mutations act as recessive embryonic lethals. Animals survive to the end of embryogenesis and have normal thoracic, abdominal, and caudal segments. However, the head is abnormal, and shows defects in derivatives of all of the gnathocephalic segments. There is no obvious homeotic transformation in these animals. Analysis of earlier stages shows abnormalities in the process of head involution. X-ray-induced clones of lab- cells demonstrate that lab function is unnecessary for the development of the adult thorax and abdomen. However, clones in the head fail to develop normally and show deletions in the maxilla and eye. Dorsally the posterior head capsule is transformed toward an apparent thoracic identity. A temperature conditional allele has been used to show a temperature critical period between 6 and 14 hours of embryogenesis. This period coincides with an interval in which head involution, a process disrupted by lab-, takes place. Antisera raised to lab protein have shown it to initially accumulated just anterior to the gnathocephalic region of the germ band at the early stages of segmentation. This protein also is found in a row of cells extending above the gnathal region in the procephalic lobe and more dorsally into the dorsal ridge. As segmentation, germ-band shortening and head involution proceed, the cells expressing the protein are involved in the process complexities of head involution. Finally at the end of morphogenesis, lab positive cells are found in the lateral aspects of the pharynx, the tritocerebral ganglia of the CNS, and the frontal sac. In addition to this expression in the head, lab protein is also found in endodermal cells at the posterior of the anterior midgut and the anterior cells of the posterior midgut. The position and movements of the cephalic cells accumulating lab is consistent with the interpretation that this locus is expressed in the intercalary or most anterior of the gnathal segments.
Summary (Interactive Fly)

transcription factor - homeodomain - Antp class - involved in head and brain morphogenesis - in the midgut Labial plays a role in determination and differentiation of copper cells

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

Please see the GBrowse view of Dmel\lab or the JBrowse view of Dmel\lab 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
Comments on Gene Model

An alternative transcript described in FBrf0047938 appears not to be encoded by the sequenced strain; a region of sequence polymorphism eliminates the alternative splice acceptor site.

Gene model reviewed during 5.50

Sequence Ontology: Class of Gene
Transcript Data
Annotated Transcripts
Name
FlyBase ID
RefSeq ID
Length (nt)
Assoc. CDS (aa)
FBtr0081696
2775
629
FBtr0308035
1586
213
Additional Transcript Data and Comments
Reported size (kB)

2.8, 1.2, 0.8 (northern blot)

Comments
External Data
Crossreferences
Polypeptide Data
Annotated Polypeptides
Name
FlyBase ID
Predicted MW (kDa)
Length (aa)
Theoretical pI
RefSeq ID
GenBank
FBpp0081194
67.5
629
7.83
FBpp0300396
22.3
213
10.18
Polypeptides with Identical Sequences

None of the polypeptides share 100% sequence identity.

Additional Polypeptide Data and Comments
Reported size (kDa)

629 (aa); 68 (kD predicted)

Comments
External Data
Crossreferences
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\lab using the Feature Mapper tool.

External Data
Crossreferences
Eukaryotic Promoter Database - A collection of databases of experimentally validated promoters for selected model organisms.
Linkouts
Gene Ontology (12 terms)
Molecular Function (4 terms)
Terms Based on Experimental Evidence (3 terms)
CV Term
Evidence
References
Terms Based on Predictions or Assertions (1 term)
CV Term
Evidence
References
inferred from electronic annotation with InterPro:IPR017970
(assigned by InterPro )
Biological Process (7 terms)
Terms Based on Experimental Evidence (4 terms)
CV Term
Evidence
References
inferred from genetic interaction with FLYBASE:vvl; FB:FBgn0086680
inferred from mutant phenotype
inferred from genetic interaction with FLYBASE:vvl; FB:FBgn0086680
inferred from mutant phenotype
Terms Based on Predictions or Assertions (3 terms)
CV Term
Evidence
References
Cellular Component (1 term)
Terms Based on Experimental Evidence (1 term)
CV Term
Evidence
References
inferred from direct assay
Terms Based on Predictions or Assertions (0 terms)
Expression Data
Expression Summary Ribbons
Colored tiles in ribbon indicate that expression data has been curated by FlyBase for that anatomical location. Colorless tiles indicate that there is no curated data for that location.
For complete stage-specific expression data, view the modENCODE Development RNA-Seq section under High-Throughput Expression below.
Transcript Expression
in situ
Stage
Tissue/Position (including subcellular localization)
Reference
central nervous system

Comment: reference states 12-14 hr AEL

embryonic/larval midgut

Comment: reference states 12-14 hr AEL

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

Comment: reference states 0-24 hr AEL

Comment: reference states 2-24 hr AEL

Comment: reference states >=2-4 hr AEL

Additional Descriptive Data

RNA-seq data show that CAH9 is enriched in the acidic region of the larval midgut.

Ectopic expression of lab transcripts is seen in midline cells and tracheal placodes of the trunk region in tsh mutants and in the posterior and dorsal part of the prothoracic segment in Antp mutants. In tsh Antp double mutants, lab is expressed ectopically in parasegments 4-13 due to the loss of tsh and more extensively in parasegments 4 and 5 due to loss of Antp. lab expression is unchanged in BXC mutants but ectopic lab expression is observed in the dorsal parts of trunk segments in Antp BXC mutant embryos and in Scr Antp BXC mutant embryos. In tsh Antp BXC mutants, there is more extensive ectopic expression in parasegments 4-13 than in tsh* mutations alone and when Scr function is removed as well, an additional patch of expression is observed in parasegment 3.

lab transcripts are first detected at 2-4 hr of embryogenesis. Expression has peaked by 6-8 hr, and remains constant until 16-20 hr of embryogenesis. Levels of lab transcript decline by 20-24 hr of embryogenesis, and remain at lower levels through larval stages. Transcript levels are low in pupae and transcript is undetectable in adults.

lab transcripts are first detected in ~3hr embryos and continue to be expressed through embryogenesis. A second peak of expression occurs in third instar larvae. Transcripts are detected weakly in pupae and not in adults. Transcripts are first detected by in situ hybridization in the cellular blastoderm embryo in ventro-lateral cells between 74-83% egg length and also in the most posterior somatic cells. The anterior region corresponds to the anlagen of the anterior mandibular lobe, the hypopharyngeal lobe and probably lateral parts of the procephalic lobe. During germ band extension, lab transcripts are observed just anterior to the cephalic furrow and in the invaginating posterior midgut. Expression in these regions persists as the germ band retracts.

This major lab transcript is expressed through most stages of embryonic development with highest levels between 3 and 12 hours. Transcript is detected in the central nervous system posterior to the brain and in the epithelial cells of the middle midgut. Weak signal is also detected in the posterior midgut.

Marker for
Subcellular Localization
CV Term
Polypeptide Expression
No Assay Recorded
Stage
Tissue/Position (including subcellular localization)
Reference
immunolocalization
Stage
Tissue/Position (including subcellular localization)
Reference
Additional Descriptive Data

lab and vvl expression domains in the tritocerebrum largely overlap.

Expression in procephalic neuroblasts stage 9-11: tritocerebrum - d1-8, v1-5 (all); deuterocerebrum - v2, v4

Marker for
Subcellular Localization
CV Term
Evidence
References
inferred from direct assay
Expression Deduced from Reporters
Reporter: P{0.5labHZ}
Stage
Tissue/Position (including subcellular localization)
Reference
Reporter: P{1.2labHZ}
Stage
Tissue/Position (including subcellular localization)
Reference
Reporter: P{3.65lab66a}
Stage
Tissue/Position (including subcellular localization)
Reference
Reporter: P{lab-GAL4.DR}
Stage
Tissue/Position (including subcellular localization)
Reference
Reporter: P{lab-GAL4.H}
Stage
Tissue/Position (including subcellular localization)
Reference
Reporter: P{lab-lacZ.1/546}
Stage
Tissue/Position (including subcellular localization)
Reference
parasegment 7 of visceral mesoderm

Comment: expression overlaps that of endogenous lab

Reporter: P{lab-lacZ.48/95}
Stage
Tissue/Position (including subcellular localization)
Reference
parasegment 7 of visceral mesoderm

Comment: expression is posterior to that of endogenous lab

Reporter: P{p6.0lab66A}
Stage
Tissue/Position (including subcellular localization)
Reference
Reporter: P{PZ}lab01241
Stage
Tissue/Position (including subcellular localization)
Reference
High-Throughput Expression Data
Associated Tools

GBrowse - Visual display of RNA-Seq signals

View Dmel\lab in GBrowse 2
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
FLIGHT - Cell culture data for RNAi and other high-throughput technologies
FlyAtlas - Adult expression by tissue, using Affymetrix Dros2 array
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, and Transgenic Constructs
Classical and Insertion Alleles ( 24 )
For All Classical and Insertion Alleles Show
 
Other relevant insertions
Transgenic Constructs ( 16 )
For All Alleles Carried on Transgenic Constructs Show
Transgenic constructs containing/affecting coding region of lab
Transgenic constructs containing regulatory region of lab
Deletions and Duplications ( 28 )
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 v7.1)
Homo sapiens (Human) (31)
Species\Gene Symbol
Score
Best Score
Best Reverse Score
Alignment
Complementation?
Transgene?
7 of 15
Yes
Yes
6 of 15
No
Yes
5 of 15
No
Yes
1 of 15
No
No
1 of 15
No
No
 
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
 
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
 
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
 
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
 
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
 
1 of 15
No
No
1 of 15
No
No
 
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
Model Organism Orthologs (via DIOPT v7.1)
Mus musculus (laboratory mouse) (30)
Species\Gene Symbol
Score
Best Score
Best Reverse Score
Alignment
Complementation?
Transgene?
6 of 15
Yes
Yes
5 of 15
No
Yes
 
5 of 15
No
Yes
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
 
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
 
1 of 15
No
No
1 of 15
No
No
 
1 of 15
No
No
1 of 15
No
No
 
1 of 15
No
No
 
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
Rattus norvegicus (Norway rat) (35)
5 of 13
Yes
Yes
5 of 13
Yes
Yes
4 of 13
No
Yes
2 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
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
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
Xenopus tropicalis (Western clawed frog) (28)
6 of 12
Yes
Yes
5 of 12
No
Yes
5 of 12
No
Yes
1 of 12
No
No
1 of 12
No
No
1 of 12
No
No
1 of 12
No
No
1 of 12
No
No
1 of 12
No
No
1 of 12
No
No
1 of 12
No
No
1 of 12
No
No
1 of 12
No
No
1 of 12
No
No
1 of 12
No
No
1 of 12
No
No
1 of 12
No
No
1 of 12
No
No
1 of 12
No
No
1 of 12
No
No
1 of 12
No
No
1 of 12
No
No
1 of 12
No
No
1 of 12
No
No
1 of 12
No
No
1 of 12
No
No
1 of 12
No
No
1 of 12
No
No
Danio rerio (Zebrafish) (34)
7 of 15
Yes
Yes
6 of 15
No
Yes
5 of 15
No
Yes
4 of 15
No
Yes
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
 
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
Caenorhabditis elegans (Nematode, roundworm) (7)
6 of 15
Yes
Yes
 
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
1 of 15
No
No
Arabidopsis thaliana (thale-cress) (0)
No records found.
Saccharomyces cerevisiae (Brewer's yeast) (2)
1 of 15
Yes
Yes
1 of 15
Yes
No
Schizosaccharomyces pombe (Fission yeast) (0)
No records found.
Orthologs in Drosophila Species (via OrthoDB v9.1) ( EOG09190C4F )
Organism
Common Name
Gene
AAA Syntenic Ortholog
Multiple Dmel Genes in this Orthologous Group
Drosophila suzukii
Spotted wing Drosophila
Drosophila suzukii
Spotted wing Drosophila
Drosophila simulans
Drosophila sechellia
Drosophila erecta
Drosophila yakuba
Drosophila ananassae
Drosophila pseudoobscura pseudoobscura
Drosophila persimilis
Drosophila willistoni
Drosophila virilis
Drosophila mojavensis
Drosophila grimshawi
Orthologs in non-Drosophila Dipterans (via OrthoDB v9.1) ( EOG09150BP2 )
Organism
Common Name
Gene
Multiple Dmel Genes in this Orthologous Group
Musca domestica
House fly
Musca domestica
House fly
Glossina morsitans
Tsetse fly
Lucilia cuprina
Australian sheep blowfly
Mayetiola destructor
Hessian fly
Aedes aegypti
Yellow fever mosquito
Anopheles gambiae
Malaria mosquito
Culex quinquefasciatus
Southern house mosquito
Orthologs in non-Dipteran Insects (via OrthoDB v9.1) ( None identified )
No non-Dipteran orthologies identified
Orthologs in non-Insect Arthropods (via OrthoDB v9.1) ( None identified )
No non-Insect Arthropod orthologies identified
Orthologs in non-Arthropod Metazoa (via OrthoDB v9.1) ( None identified )
No non-Arthropod Metazoa orthologies identified
Paralogs
Paralogs (via DIOPT v7.1)
Drosophila melanogaster (Fruit fly) (23)
3 of 10
2 of 10
2 of 10
2 of 10
2 of 10
2 of 10
2 of 10
2 of 10
2 of 10
2 of 10
1 of 10
1 of 10
1 of 10
1 of 10
1 of 10
1 of 10
1 of 10
1 of 10
1 of 10
1 of 10
1 of 10
1 of 10
1 of 10
Human Disease Associations
FlyBase Human Disease Model Reports
    Disease Model Summary Ribbon
    Disease Ontology (DO) Annotations
    Models Based on Experimental Evidence ( 0 )
    Allele
    Disease
    Evidence
    References
    Potential Models Based on Orthology ( 1 )
    Human Ortholog
    Disease
    Evidence
    References
    Modifiers Based on Experimental Evidence ( 0 )
    Allele
    Disease
    Interaction
    References
    Disease Associations of Human Orthologs (via DIOPT v7.1 and OMIM)
    Note that ortholog calls supported by only 1 or 2 algorithms (DIOPT score < 3) are not shown.
    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:
    Select Layout:
    Legend:
    Protein
    RNA
    Selected Interactor(s)
    Interactions Browser

    Please see the Physical Interaction reports below for full details
    protein-protein
    Physical Interaction
    Assay
    References
    Summary of Genetic Interactions
    esyN Network Diagram
    esyN Network Key:
    Suppression
    Enhancement

    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.
    InterologFinder - Protein-protein interactions (PPI) from both known and predicted PPI data sets.
    MIST (genetic) - An integrated Molecular Interaction Database
    MIST (protein-protein) - An integrated Molecular Interaction Database
    Pathways
    Signaling Pathways (FlyBase)
    Metabolic Pathways
    External Data
    Linkouts
    Genomic Location and Detailed Mapping Data
    Chromosome (arm)
    3R
    Recombination map

    3-48

    Cytogenetic map
    Sequence location
    3R:6,661,427..6,678,590 [-]
    FlyBase Computed Cytological Location
    Cytogenetic map
    Evidence for location
    84A1-84A1
    Limits computationally determined from genome sequence between P{lacW}casj1C2 and P{PZ}lab01241
    Experimentally Determined Cytological Location
    Cytogenetic map
    Notes
    References
    84A1-84A2
    (determined by in situ hybridisation)
    84A-84A
    (determined by in situ hybridisation)
    Experimentally Determined Recombination Data
    Location
    Left of (cM)
    Right of (cM)
    Notes
    Stocks and Reagents
    Stocks (17)
    Genomic Clones (27)
    cDNA Clones (14)
     

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

    cDNA clones, fully sequences
    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
        GenomeRNAi - A database for cell-based and in vivo RNAi phenotypes and reagents
        Antibody Information
        Laboratory Generated Antibodies
        Commercially Available Antibodies
         
        Other Information
        Relationship to Other Genes
        Source for database identify of

        Source for identity of: lab CG1264

        Source for database merge of
        Additional comments
        Other Comments

        lab is required for neuronal differentiation in the developing embryonic brain.

        Endoderm expression from a lab enhancer depends on multiple CREs, cAMP response elements from a Ubx enhancer. CrebB-17A binds to the Ubx cAMP response element (CRE), located in an enhancer, and ubiquitous expression of a dominant negative form of CrebB-17A reduces lab expression in the endoderm.

        Effects of overexpression of ANTP-C genes on tarsal segmentation in ss mutants is studied.

        dpp, by inducing kay, broadly defines an endodermal region which thus becomes predisposed to express lab. kay cooperates with signal-activated response factors to confer the precise pattern of lab expression in the endoderm.

        One of a class of genes with TATA-less promoters that have a subset of the conserved DPE sequence.

        Protein-DNA interactions are important for forming the lab-exd-DNA complex. Data suggests a model in which lab and exd bind DNA as a heterodimer in a head-to-tail orientation.

        A 20bp oligonucleotide from the 5' region of Mmus\Hoxb1, a homolog of lab, is sufficient to direct an expression pattern in Drosophila very similar to endogenous lab. This expression requires lab abd exd function. In vitro DNA binding studies reveal that lab requires exd to bind DNA with high affinity.

        Rescue of lab null mutants by the chicken ortholog Hoxb-1 demonstrates that the function of Hox genes is phylogenetically conserved.

        A phylogenetic analysis of the Antp-class of homeodomains in nematode, Drosophila, amphioxus, mouse and human indicates that the 13 cognate group genes of this family can be divided into two major groups. Genes that are phylogenetically close are also closely located on the chromosome, suggesting that the colinearity between gene expression and gene arrangement was generated by successive tandem gene duplications and that the gene arrangement has been maintained by some sort of selection.

        Virtually all of the P{r4/lacZ} expression in Drosophila depends on the same three conserved sequence elements involved in regulating expression in the mouse and lab expression. Expression in the head and the visceral mesoderm requires exd function.

        Expression of lab in the endoderm coincides with the copper cells and is required for their formation and maintenance.

        Ectopic expression of dpp eliminates Scr and Antp expression, attenuating abd-A expression, inducing Ubx, dpp, wg and tsh expression in the visceral mesoderm and inducing lab expression in the apposing endoderm. The result is failure of all of the morphogenetic events except formation of midgut constriction 2.

        One of the homeodomain loci identified in a screen for genes encoding DNA binding proteins capable of binding to a consensus Engrailed binding site.

        The homologs of Antp, ftz, Scr, Dfd, Ama, bcd, zen, pb and lab, but not zen2 are all present in D.pseudoobscura.pseudoobscura, in the same linear order and similarly spaced along the chromosome as in D.melanogaster.

        Comparative analysis of the homeobox sequences reveals the subdivision of the Antp-type homeobox genes into three classes early in metazoan evolution, one includes Abd-B, the second includes abd-A, Ubx, Antp, Scr, Dfd and ftz, and the third includes zen, zen2, pb and lab.

        The effect of ectopic expression of lab was investigated on the normal development of sensory organs in the embryonic PNS.

        lab gene product is not required for salivary gland development, at least up until the cuticle forms.

        ae expression is not modulated by lab. lab is expressed ectopically in embryos deficient for ae and Antp.

        Dissection of 5' sequences of labial gene reveal 2 types of cis-acting response elements: one mediates labial-dependent activity, providing evidence that labial induction in the endoderm is autoregulatory, the other responds to the dpp gene product.

        Cis-acting regulatory elements necessary for the proper spatial and temporal expression of lab have been determined.

        The roles of Dfd and lab have been studied through an analysis of their expression patterns in embryonic and imaginal tissues of mutant individuals.

        Ubx, abd-A, dpp, wg and lab have interacting gene products involved in the induction process between the visceral mesoderm and the gut epithelium in the embryo. lab antibody staining demonstrated that lab expression is restricted to midgut epithelial cells but coextends with Ubx expression in the adhering mesodermal cell layer. dpp and Ubx are required for lab expression in the midgut. lab staining is not altered in wg mutants.

        lab- flies are not viable and die at the embryo-first larval instar boundary.

        Mesodermal expression of dpp is required for lab expression in the midgut endoderm suggesting that dpp migrates from the mesoderm to endoderm to induce lab expression.

        A consequence of dpp expression in the visceral mesoderm cells of the anterior midgut is the induction of lab in the underlying endoderm cells.

        The correlation of lab mutant defects and lab gene expression was determined to increase understanding of Drosophila head segmental organization.

        A developmental genetic analysis of lab has been carried out.

        The molecular structure and spatial expression of the lab gene has been examined.

        The DNA sequences of the homeobox region of 11 Drosophila genes, including lab, have been compared.

        Null mutations act as recessive embryonic lethals. Animals survive to the end of embryogenesis and have normal thoracic, abdominal and caudal segments. However, the head is abnormal and shows defects in derivatives of all of the gnathocephalic segments. There is no obvious homeotic transformation in these animals. Analysis of earlier stages shows abnormalities in the process of head involution. X-ray-induced clones of lab- cells demonstrate that lab function is unnecessary for the development of the adult thorax and abdomen. However, clones in the head fail to develop normally and show deletions in the maxilla and eye. Dorsally the posterior head capsule is transformed toward an apparent thoracic identity. A temperature conditional allele has been used to show a temperature critical period between 6 and 14 hours of embryogenesis. This period coincides with an interval in which head involution, a process disrupted by lab-, takes place. Antisera raised to lab protein have shown it to initially accumulated just anterior to the gnathocephalic region of the germ band at the early stages of segmentation. This protein also is found in a row of cells extending above the gnathal region in the procephalic lobe and more dorsally into the dorsal ridge. As segmentation, germ-band shortening and head involution proceed, the cells expressing the protein are involved in the process complexities of head involution. Finally at the end of morphogenesis, lab positive cells are found in the lateral aspects of the pharynx, the tritocerebral ganglia of the CNS and the frontal sac. In addition to this expression in the head, lab protein is also found in endodermal cells at the posterior of the anterior midgut and the anterior cells of the posterior midgut. The position and movements of the cephalic cells accumulating lab is consistent with the interpretation that this locus is expressed in the intercalary or most anterior of the gnathal segments.

        Origin and Etymology
        Discoverer
        Etymology
        Identification
        External Crossreferences and Linkouts ( 51 )
        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/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
        BDGP expression data - Patterns of gene expression in Drosophila embryogenesis
        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.
        Fly-FISH - A database of Drosophila embryo and larvae mRNA localization patterns
        Flygut - An atlas of the Drosophila adult midgut
        GenomeRNAi - A database for cell-based and in vivo RNAi phenotypes and reagents
        iBeetle-Base - RNAi phenotypes in the red flour beetle (Tribolium castaneum)
        KEGG Genes - Molecular building blocks of life in the genomic space.
        modMine - A data warehouse for the modENCODE project
        Linkouts
        BioGRID - A database of protein and genetic interactions.
        DroID - A comprehensive database of gene and protein interactions.
        DRSC - Results frm RNAi screens
        FLIGHT - Cell culture data for RNAi and other high-throughput technologies
        FlyAtlas - Adult expression by tissue, using Affymetrix Dros2 array
        FlyCyc Genes - Genes from a BioCyc PGDB for Dmel
        FlyMine - An integrated database for Drosophila genomics
        Interactive Fly - A cyberspace guide to Drosophila development and metazoan evolution
        InterologFinder - Protein-protein interactions (PPI) from both known and predicted PPI data sets.
        MIST (genetic) - An integrated Molecular Interaction Database
        MIST (protein-protein) - An integrated Molecular Interaction Database
        Synonyms and Secondary IDs (18)
        Reported As
        Symbol Synonym
        BG:DS00004.9
        F90
        l(3)01241
        l(3)84Ac
        lab
        (Ahmad and Spens, 2019, Shokri et al., 2019, Billes et al., 2018, Li et al., 2018, Rastogi et al., 2018, Zhu et al., 2018, Karaiskos et al., 2017, Liu et al., 2017, Transgenic RNAi Project members, 2017-, Becker et al., 2016, Bürglin and Affolter, 2016, Moulton and Letsou, 2016, Peng et al., 2016, Fear et al., 2015, Saadaoui et al., 2015, Baek et al., 2013, Heffer and Pick, 2013, Mallo and Alonso, 2013, Marianes and Spradling, 2013, Hudry et al., 2012, Manning et al., 2012, Stultz et al., 2012, Weiss et al., 2012, Anderson et al., 2011, Bantignies et al., 2011, Gehring, 2011, Roy et al., 2011, Slattery et al., 2011, Strand and Micchelli, 2011, Hueber et al., 2010, Salzer et al., 2010, Scheuermann et al., 2010, Uhl et al., 2010, Yassin et al., 2010, Chopra et al., 2009, Christensen et al., 2009.2.28, Economou and Telford, 2009, Gambetta et al., 2009, Veenstra, 2009, Zhai et al., 2009, Casas-Tinto et al., 2008, Coiffier et al., 2008, Juven-Gershon et al., 2008, Kwong et al., 2008, Stultz et al., 2008, Beisel et al., 2007, Duboule, 2007, Hueber et al., 2007, Lohr et al., 2007, Negre and Ruiz, 2007, Ogishima and Tanaka, 2007, Pindyurin et al., 2007, Roy et al., 2007, Sprecher et al., 2007, Tanaka et al., 2007, Urbach, 2007, Xing et al., 2007, Casillas et al., 2006, Choksi et al., 2006, de Velasco et al., 2006, Meier et al., 2006, Noro et al., 2006, Sprecher and Hirth, 2006, Sprecher et al., 2006, Wang et al., 2006, Negre et al., 2005, Pearson et al., 2005, Percival-Smith et al., 2005, Leemans et al., 2001)
        Secondary FlyBase IDs
        • FBgn0010742
        Datasets (0)
        Study focus (0)
        Experimental Role
        Project
        Project Type
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        References (407)