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FB2026_01
,
released March 12, 2026
F90-2, F24
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
Please see the JBrowse view of Dmel\lab for information on other features
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AlphaFold produces a per-residue confidence score (pLDDT) between 0 and 100. Some regions with low pLDDT may be unstructured in isolation.
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
3.0 (northern blot)
2.8, 1.2, 0.8 (northern blot)
None of the polypeptides share 100% sequence identity.
629 (aa); 68 (kD predicted)
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.
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).
Comment: anlage in statu nascendi
Comment: reference states 12-14 hr AEL
Comment: reference states 12-14 hr AEL
Comment: enriched in acidic region
Comment: reference states 0-24 hr AEL
Comment: reference states 2-24 hr AEL
Comment: reference states >=2-4 hr AEL
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.
lab is expressed in the copper cells and the interstitial cells in the adult middle midgut.
Expression in procephalic neuroblasts stage 9-11: tritocerebrum - d1-8, v1-5 (all); deuterocerebrum - v2, v4
JBrowse - Visual display of RNA-Seq signals
View Dmel\lab in JBrowse
3-48
3-44.2
Please Note FlyBase no longer curates genomic clone accessions so this list may not be complete
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.
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.
polyclonal
lab is required for neuronal differentiation in the developing embryonic brain.
Effects of overexpression of ANTP-C genes on tarsal segmentation in ss mutants is studied.
One of a class of genes with TATA-less promoters that have a subset of the conserved DPE sequence.
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 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.
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.
Source for identity of: lab CG1264
