A truncated arm protein, lacking amino acids 34 to 87 and tagged with Tag:MYC, is expressed under the control of UASt regulatory sequences. The protein produced is constitutively active in wg signalling, but functions normally at adherens junctions.
Expressing armS10.UAS.Tag:MYC under the control of Scer\GAL4dpp.blk1 induces an ectopic wing pouch-like structure in the notum region of the wing disc, but the Dpp-positive domain appears relatively normal; cells originating from the wing disc's Dpp-positive domain show some invasiveness.
Embryos expressing armS10.Scer\UAS.T:Hsap\MYC under the control of Scer\GAL4btl.PS have supernumerary tracheal fusion cells in the dorsal trunk, visceral branch and transverse connective. The number of terminal tracheal cells is normal in most branches and only slightly reduced in the visceral branch.
When armS10.Scer\UAS.T:Hsap\MYC is expressed in dorsal cluster neurons under the control of Scer\GAL4ato.3.6 the branching pattern in the adult medulla is disturbed, giving rise to a reduced number of branches at the 3rd branching point of the grid-like structure.
Expression of armS10.Scer\UAS.T:Hsap\MYC driven by Scer\GAL4elav.PU leads to photoreceptor loss in the retina (obvious at 1 day old), locomotor defects (reduced climbing ability) and a shorter lifespan compared to controls.
Scer\GAL4dpp.PU-mediated expression of armS10.Scer\UAS.T:Hsap\MYC results in changes in gross morphology and alterations in cell fate in a region-specific manner within the wing disc, with little or no effect on the overall size of the wing pouch or cell proliferation. There is expansion of the hinge region and deformation of the wing pouch, and a slight overgrowth in the scutellar region.
Expression of armS10.Scer\UAS.T:Hsap\MYC under the control of Scer\GAL4hs.PB using four days of pulsed heat shock treatment consistently produces more follicle cells that accumulate between egg chambers. These extra follicle cells form long stalks with multiple rows of cells instead of one row in the wild type.
When armS10.Scer\UAS.T:Hsap\MYC is driven by Scer\GAL4c306 or Scer\GAL4slbo.2.6 no effect is seen on border cell migration. When armS10.Scer\UAS.T:Hsap\MYC is driven by Scer\GAL4elav-C155 no effect is seen on axon outgrowth in embryos. When armS10.Scer\UAS.T:Hsap\MYC is driven by Scer\GAL4btl.PS many aspects of tracheal development are unaffected. However in many segments a pronounced hypertrophy of the presumptive dorsal longitudinal trunk is seen, often with a corresponding reduction in the presumptive visceral branch. The resulting dorsal trunk is misshapen, often forming loops ventral to and reconnecting to the dorsal longitudinal trunk, or ventral outgrowths. These loops have a diameter more similar to that of the dorsal longitudinal trunk than that of the transverse connective.
Expression of armS10.Scer\UAS.T:Hsap\MYC under the control of Scer\GAL4bs-1348 results in the formation of moderate ectopic veins which emanate from the posterior crossvein, in addition to more severe ectopic veins along L2.
The tracheal dorsal trunk (DT) is hypertrophied when armS10.Scer\UAS.T:Hsap\MYC is expressed under the control of Scer\GAL4btl.PS, often showing ectopic branches with DT features. The visceral branches are shortened or even completely missing and contain fewer cells than in wild type (the rest of the branches contain roughly the normal number of cells). No extra tracheal cell proliferation is seen in these embryos.
Overexpression of armS10.Scer\UAS.T:Hsap\MYC driven by Scer\GAL4sd-SG29.1 greatly increases the size of the hinge region but does not affect the viability of the cells. Wings in these adult flies are wild-type in size but with many ectopic bristles. When expression of armS10.Scer\UAS.T:Hsap\MYC is driven by Scer\GAL4sd-SG29.1, the of the anterior compartment of the wing disc is covered in evenly spaced SOPs (sensory organ precursors). This phenotype is weaker than seen withy overexpression of dshScer\UAS.cAa and wgScer\UAS.cGa. These effects increase as development proceeds. Expression of wgScer\UAS.cGa during the induction of the wing primordia in the early phases of wing development by Scer\GAL4dpp.blk1, leads to an increased wing primordia which distorts the disc as the primordia invades the notum.
Scer\GAL4e22c-mediated expression transforms all cells to posterior cell fates. Action of the protein is largely inhibited when expressed in pan13a, pan2 or pan3 embryos, embryos exhibit alternate denticles and naked cuticle with portions of the lateral naked cuticle converted to denticles.
Expression of armS10.Scer\UAS.T:Hsap\MYC in type II neuroblasts or ase- immature intermediate neural progenitors (INPs) enhances the supernumerary neuroblast phenotype seen in bratDG19310/brat11 larval brains, whereas expression in ase+ immature INPs does not (different insertions of Scer\GAL4GMR9D11 are used to drive expression in each case).
Expression of armS10.Scer\UAS.T:Hsap\MYC under the control of Scer\GAL4sd.PU significantly suppresses the overproliferation seen in lace2 mutant wing disc clones, in terms of both frequency and severity of the phenotype.
Expression of armS10.Scer\UAS.T:Hsap\MYC under the control of Scer\GAL4sd.PU significantly suppresses the severity of overproliferation seen in ACC1 mutant wing disc clones, but does not reduce the frequency of discs exhibiting overgrowth.
The leading edge cell in the anterior compartment just anterior to the parasegment boundary is transformed into an ectopic mixer cell in wgl-17 embryos expressing armS10.Scer\UAS.T:Hsap\MYC under the control of Scer\GAL4en-e16E assayed by marker expression (in the abdominal segments of wild-type embryos at the end of dorsal closure, the "mixer cell" moves across the segment boundary from the anterior compartment to the posterior compartment, but the cell in the equivalent position relative to the parasegment boundary does not show this "mixing" behaviour).
The co-expression of armS10.Scer\UAS.T:Hsap\MYC enhances the eye defects in adults expressing NICN.Scer\UAS driven by Scer\GAL4ey.PS, with associated wrinkling and distortion of third instar larva eye discs, but no obvious differentiation defects are visible in these discs.
armS10.Scer\UAS.T:Hsap\MYC with Scer\GAL469B weakly suppresses the dorsal hole phenotype of hep1 mutants, as well as rescuing adhesion between the dorsal epidermis and the amnioserosa. However, it fails to rescue the formation of an actin cable in leading edge cells of these embryos.
Co-expression of armS10.Scer\UAS.T:Hsap\MYC can rescue both the wing notching phenotype and loss of sensory bristles caused by expression of dlpScer\UAS.cBa under the control of Scer\GAL4C96. In addition, ectopic margin bristles close to the wing margin are seen in these flies.
When expression is driven by Scer\GAL4en-e16E in a wgl-17 background strips of segmentally repeated smooth cuticle occur. There are fewer large row 5 type denticles than in the single wg mutant, and row 6 type denticles do not develop. The denticles that do form are of the row 2 or 3 type. The denticle pattern shows some mirror symmetry. Denticles point away from the nearest region of smooth cuticle.