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General Information
Symbol
Dmel\shot3
Species
D. melanogaster
Name
FlyBase ID
FBal0051150
Feature type
allele
Associated gene
Associated Insertion(s)
Carried in Construct
Key Links
Mutagen
Nature of the Allele
Mutations Mapped to the Genome
 
Type
Location
Additional Notes
References
Associated Sequence Data
DNA sequence
Protein sequence
 
 
Progenitor genotype
Cytology
Nature of the lesion
Statement
Reference
Expression Data
Reporter Expression
Additional Information
Statement
Reference
 
Marker for
Reflects expression of
Reporter construct used in assay
Human Disease Associations
Disease Ontology (DO) Annotations
Models Based on Experimental Evidence ( 1 )
Disease
Evidence
References
Modifiers Based on Experimental Evidence ( 1 )
Disease
Interaction
References
Comments on Models/Modifiers Based on Experimental Evidence ( 0 )
 
Disease-implicated variant(s)
 
Phenotypic Data
Phenotypic Class
Phenotype Manifest In

axon & pCC neuron

centrosome & ovary | germ-line clone

chordotonal organ & axon | lateral

egg chamber & follicle cell | somatic clone

microtubule & ovary | germ-line clone

mushroom body & axon

synapse & neuromuscular junction

Detailed Description
Statement
Reference

In cultured neurons from stage 11 shot3 homozygous embryos, there are significantly more microtubules in axon shaft filopodia, as compared to controls. In both shot3 hetero- and homozygous conditions, the axonal microtubules are significantly more disorganized than in controls.

The medulla in shot3 heterozygous adults shows axon swelling with microtubule disorganization.

The microtubule organization in shot3 mutant follicle cell clones is perturbed as their apical enrichment is lost.

Cultured primary neurons derived from homozygous embryos have a significantly reduced axon length compared to wild-type controls.

shot3/shotVV third instar larvae show overgrowth (increase in bouton number) at the neuromuscular junction.

shot3/shotVV axons show enhanced regenerative axonal sprouting compared to controls after a crushing injury.

shot3/Df(2R)MK1 primary neuronal cultures show a significantly reduced axonal length compared to controls. They also show an increase of neurons with unbundled microtubules - these microtubules display irregular trajectories and frequent loops in axons and growth cones.

Scer\GAL4sca-537.4-mediated expression of shotLC.Scer\UAS.T:Avic\GFP fails to restore the microtubule unbundling and axonal length phenotypes of shot3/Df(2R)MK1 primary neuronal cultures.

shot3/Df(2R)MK1 primary neuronal cultures show a significant reduction in filopodia number.

Scer\GAL4sca-537.4-mediated expression of shotLA-ΔEF-hand.Scer\UAS.T:Avic\GFP fails to fully rescue the reduced filopodia phenotype of shot3/Df(2R)MK1 primary neuronal cultures.

In shot3 embryos, the pCC axon aberrantly crosses the midline in 16% of CNS segments.

Homozygous germ-line clones produce egg chambers, but they do not progress beyond stage 7 of oogenesis. Each mutant egg chamber contains 16 nuclei, and the pattern of divisions is also normal. Fusome structure and persistence appear normal. In addition the fusome/spectrosome is still distributed asymmetrically in early stem cell/cystoblast division, with the larger portion being found in the stem cell after division. In mutant cysts all of the nuclei, including the two at the posterior of the egg chamber appear polyploid: All of the germ-line cells adopt a nurse cell fate, no oocyte is specified. The synaptonemal complex accumulates in none or two or more cells all throughout region 2a of the cyst, but this accumulation fails to refine onto one cell only and is always lost region 2b. In wild-type ovaries, microtubules are highly concentrated around the fusome from region 2a on, and in region 2b and 3 a microtubule organising centre (MTOC) is visible in the oocyte. This organisation and concentration of microtubules is lost in mutant germ-line clones; microtubules fail to concentrate around the fusome., and an MTOC does not form in region 2b or 3. the migration of the centrosomes into the oocyte normally seen in wild-type ovaries fails to occur.

Mutant mushroom body neuroblast clones examined in the adult show abnormal processes projecting out from the calyx. Mutant mushroom body neuroblast clones have a significant reduction in cell number compared to control clones.

shot3 germline clones do not produce viable eggs. shot3 clones of cells are often double-layered in egg chambers from stage 6-7 onwards, with actin accumulation at the contacts between the two layers. Double-layered clones are only detected in cells overlying the oocyte, and at stage 10 of oogenesis are generally found in the posterior half of the follicle cells covering the oocyte. Microtubule levels and organisation, integrin localisation and oocyte elongation are normal in shot3 mutant cells.

Mutant embryos show defects in motor axon extension; the ISN stalls at the approximate position where it would normally make the second dorsalmost muscle contact, the SNa stalls where it would normally bifurcate and the ISNb stalls in the ventral muscle field and fails to reach muscle 12. Mutant embryos also show defects in sensory axon extension.

The tracheal dorsal trunk lumen is discontinuous at 75% of anastomosis sites in stage 14 or older mutant embryos. Lateral trunk connections and all anastomoses at the dorsal midline are affected. The overall branching pattern of trachea within hemisegments appears normal. 6% of tracheal dorsal trunk connections form apparently normally and 19% are constricted relative to wild type. Fusion cells appear to be present at the dorsal trunk anastomosis sites. Microtubules are not apically located at anastomosis sites of the tracheal dorsal trunk in mutant embryos, in contrast to wild type, though they remain largely at the cell periphery. F-actin accumulates apically in the tracheal cells but the lumen does not extend through the fusion cells at the anastomosis site.

shot3 mutants show strong reduction of output synapses at the NMJ, while this phenotype is not seen in the CNS.

The lateral chordotonal sensory axons arrest at variable stages before reaching the central nervous system (CNS); 93% extend towards the intersegmental nerve (ISN) and stall or fail to reach the ISN, 7% travel a significant distance within the ISN, but none of the axons reach the CNS border. The morphology of the LCH growth cones is normal, with the growth cone adopting the general morphology of wild-type growth cones at the place where they stall. Defects in LCH dendrite morphology are seen in shot3 and shot2/shot3 mutant embryos. 90-100% of the motor axons of all three major pathways (ISN, SNa and ISNb) stall prematurely in late stage 16/stage 17 homozygous embryos. 3% of ISN axons lack the most dorsal terminal arborisation, 68% lack the 2 most dorsal terminal arborisations and 24% lack all three terminal arborisations. 1% of ISN axons stall before entering the dorsal muscle field. The SNa and ISNb motor axons stall before reaching their muscle targets. 75% of ISNb motor axons stall in the ventral muscle field (somewhere between muscle 6 and muscle 13) and 14% stall at the muscle field border. 33% of SNa axons have one branch missing (wild-type axons form two branches), 38% lack both branches and 17% stall over the ventral muscles or are absent. Some SNa and ISNb motor axon bundles fail to exit the CNS successfully or stall earlier than the muscle field entry points in shot3/Df(2R)CX1 embryos. 61% of ISNb motor axons stall in the ventral muscle field (somewhere between muscle 6 and muscle 13) and 20% stall at the muscle field border. 40% of ISN axons lack the 2 most dorsal terminal arborisations and 42% lack all three terminal arborisations. 17% of ISN axons stall before entering the dorsal muscle field. 24% of SNa axons have one branch missing (wild-type axons form two branches), 60% lack both branches and 8% stall over the ventral muscles or are absent. 6% of ISN axons lack the most dorsal terminal arborisation, 48% lack the 2 most dorsal terminal arborisations and 43% lack all three terminal arborisations in shot2/shot3 embryos. 57% of ISNb motor axons stall in the ventral muscle field (somewhere between muscle 6 and muscle 13) and 30% stall at the muscle field border. 46% of SNa axons have one branch missing (wild-type axons form two branches) and 28% lack both branches. Muscle morphology and number is normal in late stage 16 homozygous embryos.

Mushroom body neuroblast clones induced using the MARCM system exhibit drastic axon projection defects compared with wild type controls. The origin of the pathfinding errors appears to be near the dendritic projection area. In the majority of cases the abnormal axon bundles do project in a generally wild type direction, towards the midline region. Some even eventually fuse with the medial lobe, as they do in the wild type.

Mutant phenotype as assayed by Ecol\lacZrp staining: longitudinal connectives missing. Mutant phenotype of lateral chordotonal axons includes: missing axons.

External Data
Interactions
Show genetic interaction network for Enhancers & Suppressors
Phenotypic Class
Enhanced by
Statement
Reference

shot3/shot[+], sli2 has abnormal neuroanatomy | embryonic stage phenotype, enhanceable by exba[+]/kra2

shot3 has abnormal neuroanatomy | embryonic stage phenotype, enhanceable by exba[+]/kra2

robo12, shot3 has abnormal neuroanatomy | embryonic stage phenotype, enhanceable by exba[+]/kra2

Suppressed by
Enhancer of
Statement
Reference
Phenotype Manifest In
Enhanced by
Statement
Reference

shot3/shot[+], sli2 has axon & pCC neuron phenotype, enhanceable by exba[+]/kra2

shot3 has axon & pCC neuron phenotype, enhanceable by exba[+]/kra2

shot3 has axon & pCC neuron phenotype, enhanceable by kra2/kra1

robo12, shot3 has axon & pCC neuron phenotype, enhanceable by exba[+]/kra2

Suppressed by
NOT suppressed by
Statement
Reference

shot3 has axon phenotype, non-suppressible by CLIP-190KO/CLIP-190KO

Enhancer of
Statement
Reference

shot3/shot3 is an enhancer of axon | embryonic stage phenotype of Efa6GX6w-

shot3/shot[+] is an enhancer of axon | adult stage phenotype of Efa6GD14945, Scer\GAL4GMR31F10

shot3/shot[+] is an enhancer of medulla | adult stage phenotype of Efa6GD14945, Scer\GAL4GMR31F10

shot3/shot[+] is an enhancer of axon & pCC neuron phenotype of sli2

shot3 is an enhancer of axon & pCC neuron phenotype of robo12

shot3/shot[+] is an enhancer of axon & pCC neuron phenotype of kra2/kra1

Suppressor of
Statement
Reference

shot3/shot[+] is a suppressor of embryonic head phenotype of miraαTub67C.mGFP6

Additional Comments
Genetic Interactions
Statement
Reference

The decrease in axon length seen in cultured primary neurons derived from homozygous shot3 embryos is unchanged if the embryos are also homozygous for CLIP-190KO.

wnd2/+ partially suppresses the increase in bouton number seen at the neuromuscular junction in shot3/shotVV third instar larvae.

wnd2/wnd3 fully suppresses the increase in bouton number seen at the neuromuscular junction in shot3/shotVV third instar larvae.

Expression of either kayFbz.Scer\UAS or bskK53R.Scer\UAS under the control of Scer\GAL4elav.PU suppresses the increase in bouton number seen at the neuromuscular junction in shot3/shotVV third instar larvae.

The bicaudal phenotype of embryos derived from miraαTub67C.T:Avic\GFP-m6/+ females is suppressed if the females are also heterozygous for shot3.

The axon midline phenotype of sli2/+ embryos is enhanced in sli2/+; exba2/+ and shot3/+, sli2/+ double mutants. The phenotype is further enhanced in shot3/+, sli2/+; exba2/+ triple mutants.

The frequency of aberrant pCC axon midline crossovers in shot3/+; exba1/exba2 and shot3/shot3; exba2/+ double mutant embryos is significantly greater than in either single mutant homozygous embryos. The midline crossing phenotype is slightly more severe in shot3/shot3; exba1/exba2 embryos compared to shot3/shot3; exba2/+ embryos, while shot3/+; exba2/+ embryos show no significant midline defects.

The pCC axon midline crossing phenotype of robo2 embryos is dramatically enhanced in robo2/+; exba2/+ embryos and in shot3, robo2/+ embryos. The phenotype is further enhanced in shot3, robo2/+; exba2/+ embryos.

Xenogenetic Interactions
Statement
Reference
Complementation and Rescue Data
Comments

Expression of shotLA.Scer\UAS.T:Avic\GFP under the control of Scer\GAL4elav.PU rescues the increase in bouton number seen at the neuromuscular junction in shot3/shotVV third instar larvae, while expression under the control of Scer\GAL4how-24B fails to rescue the phenotype.

Expression of either shotLA-ΔPlakin.Scer\UAS.T:Avic\GFP or shotLA-Δrod1.Scer\UAS.T:Avic\GFP under the control of Scer\GAL4elav.PU rescues the increase in bouton number seen at the neuromuscular junction in shot3/shotVV third instar larvae.

Expression of either shotLC.Scer\UAS.T:Avic\GFP, shotLA-ΔEF-hand.Scer\UAS.T:Avic\GFP or shotLA-ΔGAS2.Scer\UAS.T:Avic\GFP under the control of Scer\GAL4elav.PU fails to rescue the increase in bouton number seen at the neuromuscular junction in shot3/shotVV third instar larvae.

Scer\GAL4sca-537.4-mediated expression of shotLC.Scer\UAS.T:Avic\GFP fails to restore the microtubule unbundling and axonal length phenotypes of shot3/Df(2R)MK1 primary neuronal cultures.

Scer\GAL4sca-537.4-mediated expression of shotLA-ΔEF-hand.Scer\UAS.T:Avic\GFP fully restores the microtubule unbundling and axonal length phenotypes of shot3/Df(2R)MK1 primary neuronal cultures.

Scer\GAL4sca-537.4-mediated expression of shotLC.Scer\UAS.T:Avic\GFP fully rescues the reduced filopodia phenotype of shot3/Df(2R)MK1 primary neuronal cultures.

Scer\GAL4sca-537.4-mediated expression of shotLA-ΔEF-hand.Scer\UAS.T:Avic\GFP fails to fully rescue the reduced filopodia phenotype of shot3/Df(2R)MK1 primary neuronal cultures.

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Mutant
Wild-type
Stocks (3)
Notes on Origin
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External Crossreferences and Linkouts ( 0 )
Synonyms and Secondary IDs (1)
References (30)