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General Information
Symbol
Dmel\SmnX7
Species
D. melanogaster
Name
FlyBase ID
FBal0241134
Feature type
allele
Associated gene
Associated Insertion(s)
Carried in Construct
Also Known As
Df(3L)SmnX7
Key Links
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

Imprecise excision of the progenitor insertion, resulting in a deletion that removes almost the entire Smn transcription unit (the deletion extends from 93bp upstream of the transcription start site through all but the final 44bp of the 3'UTR) without affecting nearby loci.

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 )
Modifiers Based on Experimental Evidence ( 0 )
Disease
Interaction
References
Comments on Models/Modifiers Based on Experimental Evidence ( 1 )
 

Comparison of RNA deep-sequencing expression profiles of SmnX7/Smnf01109 and wild-type larvae argue against a minor-intron-dependent etiology for spinal muscular atrophy.

Disease-implicated variant(s)
 
Phenotypic Data
Phenotypic Class
Phenotype Manifest In
Detailed Description
Statement
Reference

SmnX7 homozygous larvae show severe decrease in locomotor ability, as compared to controls.

Expression of SmndsRNA.FL.Scer\UAS.WIZ under the control of Scer\GAL4tub.PU in a SmnX7 background results in a fully penetrant pupal lethality, with none of the pupae reaching a pigmented developmental stage.

SmnX7/SmnX7 third instar larvae are smaller, have significantly decreased muscle surface area, show significantly decreased locomotion velocity, have disrupted rhythmic motor activity (significantly increased spontaneous inter-spike intervals), and at the neuromuscular junction show significantly increased evoked excitatory postsynaptic potential amplitude, increased miniature excitatory postsynaptic potential frequency and increased quantal content compared to wild type.

SmnX7/Smn73Ao or SmnX7/SmnE33 third instar larvae have significantly increased evoked excitatory postsynaptic potential amplitude at the neuromuscular junction.

SmnX7 mutant larvae exhibit an aberrant increase in evoked excitatory postsynaptic potential amplitudes at the neuromuscular junction to ~125% of controls. Muscle 6 in hemisegment A3 of SmnX7 mutant larvae is reduced in size, locomotion is decreased and rhythmic motor activity is altered.

20-30% of Smnf01109/SmnX7 mutant larvae are long lived and can survive for many days without undergoing metamorphosis or exhibiting the wandering behaviour typical of the late third instar.

SmnX7/+ third instar larvae have a similar number of boutons per muscle at the neuromuscular junction, compared to controls.

External Data
Interactions
Show genetic interaction network for Enhancers & Suppressors
Phenotypic Class
Phenotype Manifest In
Additional Comments
Genetic Interactions
Statement
Reference

Presence of SmnX7 or Df(3L)ED4782 does not result in significant progressive flight or survival phenotypes in flies with expression of Gem3ΔN.Scer\UAS driven by Scer\GAL4Mef2.PR.

Expression of stasScer\UAS.cLa either pan-neuronally under the control of Scer\GAL4n-syb.PS or in cholinergic neurons using Scer\GAL4Cha.7.4 rescues the increase in neuromuscular junction evoked excitatory postsynaptic potential (eEPSP) amplitudes seen in SmnX7 mutant larvae. The reduction in muscle size is rescued to 80% of that in control larvae. Expression of stasScer\UAS.cLa in the glutamatergic motor neurons using the Scer\GAL4VGlut-OK371 driver fails to rescue either the eEPSP or muscle size phenotypes. The locomotor activity defects seen in SmnX7 mutants are not rescued by any of the three drivers.

Xenogenetic Interactions
Statement
Reference
Complementation and Rescue Data
Partially rescued by

SmnX7 is partially rescued by SmnTag:FLAG

SmnX7 is partially rescued by SmnTag:FLAG

SmnX7 is partially rescued by SmnTag:FLAG

SmnX7 is partially rescued by SmnTag:FLAG

Not rescued by
Comments

Expression of one copy of SmnM194R.T:Zzzz\FLAG fails to rescue the larval lethality seen in homozygous SmnX7 mutants. The larvae are similar in size to SmnX7 mutants.

Expression of one copy of SmnY203C.T:Zzzz\FLAG fails to rescue the larval lethality seen in homozygous SmnX7 mutants.

Expression of one copy of SmnG206S.T:Zzzz\FLAG fails to rescue the larval lethality seen in homozygous SmnX7 mutants.

Expression of one copy of SmnD20V.T:Zzzz\FLAG partially rescues the larval lethality seen in homozygous SmnX7 mutants.

Expression of one copy of SmnF70S.T:Zzzz\FLAG partially rescues the larval lethality seen in homozygous SmnX7 mutants.

Expression of one copy of SmnG73R.T:Zzzz\FLAG partially rescues the larval lethality seen in homozygous SmnX7 mutants.

Expression of one copy of SmnI93F.T:Zzzz\FLAG partially rescues the larval lethality seen in homozygous SmnX7 mutants.

Expression of one copy of SmnV72G.T:Zzzz\FLAG overcomes the larval lethality seen in homozygous SmnX7 mutants but the resulting flies are pupal lethal.

Expression of one copy of SmnY107C.T:Zzzz\FLAG partially rescues the larval lethality seen in homozygous SmnX7 mutants.

Expression of one copy of SmnT205I.T:Zzzz\FLAG partially rescues the larval lethality seen in homozygous SmnX7 mutants.

Expression of one copy of SmnG210C.T:Zzzz\FLAG partially rescues the larval lethality seen in homozygous SmnX7 mutants.

Expression of one copy of SmnG210V.T:Zzzz\FLAG partially rescues the larval lethality seen in homozygous SmnX7 mutants.

Decreased muscle surface area, locomotor defects, increased inter-spike intervals and increased evoked excitatory postsynaptic potential (eEPSP) amplitude in SmnX7/SmnX7 third instar larvae are rescued by ubiquitous (Scer\GAL4da.PU), pan-neuronal (Scer\GAL4nSyb.PS) or cholinergic (Scer\GAL4ChAT.7.4) expression of SmnScer\UAS.T:Zzzz\FLAG; these phenotypes are not rescued when expression is driven by larval muscle-specific Scer\GAL4G14, glutamatergic Scer\GAL4VGlut-OK371, motor-neuron specific Scer\GAL4RapGAP1-OK6, GABAergic (Scer\GAL4Gad1.3.098), Scer\GAL41003.3 or Scer\GAL4ppk.1.9. Expression of SmnScer\UAS.T:Zzzz\FLAG with Scer\GAL4clh201 or Scer\GAL4NP2225 rescues the increased inter-spike intervals and increased eEPSP amplitude, partially rescues the decreased muscle surface area, but fails to rescue the locomotion defect in SmnX7/SmnX7 third instar larvae.

SmnScer\UAS.T:Zzzz\FLAG driven by Scer\GAL4elav.Switch.PO in the presence of RU486 rescues SmnX7/SmnX7 muscle size, locomotion (partially), inter-spike intervals and eEPSP defects if SmnScer\UAS.T:Zzzz\FLAG expression is induced immediately after hatching (if induced 48 or 96 hours after hatching rescue is partial apart from full rescue of eEPSP).

Expression of SmnT:Zzzz\FLAG in a Smnf01109/SmnX7 mutant background results in >70% rescue of lethality. The resulting adults are fertile with no apparent defects in flight or motility. Pupation and eclosion occurs a day later than in wild type controls. Expression of SmnT:Zzzz\FLAG also rescues the motility and burrowing defects seen in Smnf01109/SmnX7 mutant larvae.

Expression of SmnAct5C.T:Zzzz\FLAG fails to rescue the larval lethality seen in Smnf01109/SmnX7 mutants.

Expression of SmnT205I.T:Zzzz\FLAG fully rescues the larval lethality seen in Smnf01109/SmnX7 mutants. However lethality in these mutants occurs at the pupal stage, with only 25% of mutants eclosing as adults. Pupation and eclosion occurs a day later than in wild type controls. Expression of SmnT:Zzzz\FLAG also largely rescues the motility defects seen in Smnf01109/SmnX7 mutant larvae, whereas the burrowing defects are fully rescued.

Images (0)
Mutant
Wild-type
Stocks (0)
Notes on Origin
Discoverer
External Crossreferences and Linkouts ( 0 )
Synonyms and Secondary IDs (6)
References (18)