αPS2, αPS2, PS2, αPS2 integrin, PS2α
Low-frequency RNA-Seq exon junction(s) not annotated.
Supported by strand-specific RNA-Seq data.
Gene model reviewed during 5.52
5.7 (northern blot)
1394 (aa); 140 (kD observed)
Heterodimer of an alpha and a beta subunit. The alpha subunit is composed of a heavy and a light chain linked by a disulfide bond. Alpha-PS2 associates with beta-PS.
The heavy-light chain cleavage site is either in 1230-1231, or 1233-1234, or 1243-1244.
Click to get a list of regulatory features (enhancers, TFBS, etc.) and gene disruptions (point mutations, indels, etc.) within or overlapping Dmel\if using the Feature Mapper tool.
if transcripts are expressed throughout development and in adults. In embryos, they are first detected at stage 4 in the presumptive mesoderm. They continue to be expressed in mesodermal cells after invagination. In third instar larval wing discs, if transcripts are primarily restricted to the ventral compartment and to the peripodial membrane.
if accumulates at the transitory, anterior attachment site of dorsal acute muscle 3 of stage 14 embryos, and is lost after the final attachment sites are selected by stage 16.
if staining is seen in follicle cell membranes by staining of unfixed, unpermeabilized ovaries followed by fixation and dissection.
if protein is first detected in stage 10 embryos in the mesoderm where it is basally concentrated in cuboidal cells which lie on the ectoderm. After the somatic and visceral mesoderm separates, if protein is found on the basal cell surfaces of the visceral myoblasts when they attach to the foregut, midgut, and hindgut. It is also found at the sites of attachment of the somatic muscles. Protein was also detected in the gonadal sheath and in the interstitial cells of the gonad In third instar larval wing discs, if protein is primarily restricted to the ventral compartment.
GBrowse - Visual display of RNA-Seq signalsView Dmel\if in GBrowse 2
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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.
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.
dsRNA made from templates generated with primers directed against this gene tested in RNAi screen for effects on Kc167 and S2R+ cell morphology.
RNAi screen using dsRNA made from templates generated with primers directed against this gene causes a phenotype when assayed in S2R+ cells: cells become round and detached. Kc167 cells are unaffected.
if is required in the visceral mesoderm for normal migration of the endodermal midgut cells over the visceral mesoderm in the developing embryo.
Class I and class II alleles fully complement class IV alleles. Class II alleles fully complement class III alleles. if13ts class I allele fully complements class II alleles, but the transheterozygotes between other class I alleles and class III allele generally die, although a few adult escapers are observed.
Mutational analysis reveals if is required for the development of the adult halteres and legs, as well as the wing. if is required for the formation of the somatic muscle sarcomeric structure, rather than for its maintenance. The function of if in the morphogenesis of the midgut and nerve cord is distinct from its function in muscle attachment and sarcomeric structure.
The functional significance of the cytoplasmic domains of the if, mew and mys subunits of the Position Specific (PS) integrin family are studied by analysing the relationship between the cytoplasmic domain structure and function in the context of a developing organism. The cytoplasmic tail of if is essential for both embryonic and postembryonic processes.
Modulation of integrin function through the cytoplasmic domain of if is essential for embryonic morphogenesis.
if is essential for the adhesion of muscle and epidermal hemiadherens junctions to extracellular matrix at muscle attachment sites in the developing embryo.
The ability of two different integrin α subunits (encoded by mew and if) to substitute for each other during embryonic development has been studied. The two α subunits encoded by mew and if are not equivalent and have distinct functions which reside in the extracellular domains.
Clonal analysis demonstrates that the different integrins, mew and if, are required on opposite wing epithelia. An early integrin-dependent process, not obviously required for prepupal adhesion, is essential to permit subsequent wing morphogenesis.
if and mys can be localised by an intracellular mechanism within the muscles. Direct localisation of the transmembrane protein to sites of integrin function occurs in cells that lack endogenous mys and if or cells that lack extracellular signals from the tendon cells.
Phenotypic analysis of mew, if and mys embryos suggests multiple roles for PS integrins in the adhesion of cells and in the formation, organization and migration of embryonic tissues. Although the proteins are often expressed in adjacent embryonic tissues, this distribution does not necessarily reflect equivalent requirements. The complete loss of both α subunits, encoded by mew and if, does not produce all the phenotypes observed in embryos lacking the mys encoded β subunit.
Molecular and genetic analysis prove that the αPS2 integrin subunit is encoded by the if locus. Comparison of the null phenotypes of mys (encoding the ΒPS integrin subunit) and if rules out a model where PS integrin function occurs solely by the direct interaction of the two PS integrins, αPS1ΒPS and αPS2ΒPS.
Muscle phenotype of mutants studied using polarised light microscopy and antibody staining to detect Mhc-lacZ reporter gene expression in muscles.
Structural gene for the α-subunit of position specific integrin 2 (PS2), a large transmembrane protein (Bogaert, Brown and Wilcox, 1987). The β-subunit can associate with either of the two α-subunits, PS1 or PS2 (Brower et al., 1984; Wilcox et al., 1984). Both α and β integrin are expressed in embryonic and larval tissues. In early development, PS2 is found in the mesoderm, localized to muscle attachments (Bogaert, Brown and Wilcox, 1987). Later, PS1 is expressed in the presumptive dorsal epithelium of the third instar imaginal wing discs; also, PS2 is found in the ventral epithelium, both integrins being important for the joining of the dorsal and ventral surfaces of the wing blade (Brower and Jaffe, 1989). Null mutations cause embryonic lethality (Wilcox, DiAntonio and Leptin, 1989). In the mutant if1, the adult wing is inflated with lymph and smaller than normal; venation is defective. Wings later become dry and blistered.