sSpi, s-spi, l(2)01068, l(2)s3547
ligand for Epidermal growth factor receptor - Egf/Tgf alpha homolog - required for the differentiation of all ommatidial cell types, with the exception of R8 - Spi is found on retinal axons that project into the lamina; this transported Spitz is required for lamina cartridge neuron differentiation
Please see the JBrowse view of Dmel\spi 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.
Annotated transcripts do not represent all supported alternative splices within 5' UTR.
Gene model reviewed during 5.48
2.5, 2.0 (northern blot)
230 (aa); 26 (kD)
Interacts with Star via the lumenal domain.
Proteolytic processing by Rhomboid occurs in the Golgi. Cleavage takes place within the transmembrane domain close to residue 144 and the active growth factor is released.
N-glycosylated and O-glycosylated.
Click to get a list of regulatory features (enhancers, TFBS, etc.) and gene disruptions (point mutations, indels, etc.) within or overlapping Dmel\spi 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: maternally deposited
Comment: reported as head epidermis primordium
Comment: reported as head epidermis primordium
Comment: reported as head epidermis primordium
Comment: reported as dorsal/lateral sensory complexes
spi is expressed in small diploid cells located basally in the epithelium, which are likely intestinal stem cells.
spi is broadly expressed in the optic lobe.
spi transcript is expressed in the adult midgut precursor cells.
JBrowse - Visual display of RNA-Seq signals
View Dmel\spi in JBrowse
2-53.7
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
New stable cell line derived from S2-unspecified : Stable cell lines that express the full length spi protein (designated S2:spi ) or a truncated, secreted form of spi protein (designated S2:sspi ) were created. Stable cell lines that express Egfr were created and designated S2:DER1b and S2:DER2f . The S2:DER2f cell line is a constitutive Egfr-expressing cell line that was subsequently called D2F.
Identified as a candidate gene for hypoxia-specific selection (via an experimental evolution paradigm) that is also differentially expressed between control and hypoxia-adapted larvae.
spi is not required for patterning of the dorsal anterior follicular epithelium.
Area matching Drosophila EST AA201448. This EST forms a 856bp contig with ESTs AA438721 and AA247046.
Two EMS induced alleles were identified in a screen for mutations affecting commissure formation in the CNS of the embryo.
spi is required in follicle cells for dorsal-anterior patterning of the egg.
In vivo culture of mutant discs from genotypes that are normally embryonic lethal demonstrates spi has no role in wing disc growth.
spi acts in photoreceptor recruitment in the developing retina.
Facilitating the expression of spi, rho and S is the only sim-dependent contribution of the midline to patterning the ventral ectoderm, since the mutant sim ectodermal defects can be overcome by expression of secreted spi in the ectoderm. These results suggest a mechanism for generating a graded distribution of secreted spi, which may subsequently give rise to graded activation of Egfr in the ectoderm.
The autosomal "FLP-DFS" technique (using the P{ovoD1-18} P{FRT(whs)} P{hsFLP} chromosomes) has been used to study the zygotic lethal mutation.
In spi mutants the pre-duct cells are converted to a pre-gland fate.
In salivary gland development the activity of fkh prevents the expression of duct-specific cells, and in preduct cells the spi group signalling pathway prevents the expression of gland specific markers. fkh is repressed by spi group signalling, which is strongest in the most ventral cells of the epidermis.
The spi product triggers the Egfr signaling cascade. Graded activation of the Egfr pathway may normally give rise to a repertoire of discrete cell fates in the ventral ectoderm and graded distribution of spi may be responsible for the graded activation. The rho and S products may act as modulators of Egfr signaling. Epistatic relationships suggest that rho and S may normally facilitate processing of the spi precursor.
spi is required for photoreceptor determination; mutations modify the phenotype caused by ectopic expression of rho in the eye. Mosaic analysis suggest spi produces a diffusible signal during ommatidial development. Other members of the spi group and Egfr also interact with rho, in a pattern that suggests a model in which rho can act as a mediator of a ligand-receptor interaction between spi and Egfr in the developing eye.
Clonal analysis demonstrates spi is required in the founding photoreceptor cells.
Embryonic lethal. Denticle bands narrower than normal; first row often missing; reversal of polarity between anterior and posterior rows not seen; irregular fusion in midline of adjacent dentical bands. Keilin's organs missing or strongly reduced. Labrum, antennal-maxillary complex and labial sense organ reduced in size; right and left halves of head skeleton fused to produce pointed appearance. Tail region normal. Right and left halves of ventral ganglia of the central nervous system closer together than normal resulting in shorter commissures. The cells in the CNS that stain with anti-eve+ antibodies are closer together in spi- than in wild type.
spi gene product is required for the proper development of the ventralmost cuticle and the CNS midline.
Source for merge of: spi anon-WO0118547.158
Source for merge of spi anon-WO0118547.158 was sequence comparison ( date:051113 ).
