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General Information
Symbol
Dmel\β-Specem21
Species
D. melanogaster
Name
FlyBase ID
FBal0117938
Feature type
allele
Associated gene
Associated Insertion(s)
Carried in Construct
Also Known As
βspecem21
Key Links
Allele class
Nature of the Allele
Allele class
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

Amino acid replacement: W?term.

Mutation is in repeat 13.

Nucleotide substitution: A?G.

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 ( 0 )
Disease
Evidence
References
Modifiers Based on Experimental Evidence ( 0 )
Disease
Interaction
References
Comments on Models/Modifiers Based on Experimental Evidence ( 0 )
 
Disease-implicated variant(s)
 
Phenotypic Data
Phenotypic Class
Phenotype Manifest In
Detailed Description
Statement
Reference

β-Specem21 hemizygotes are lethal but heterozygotes are fully viable; β-Specem21 heterozygotes expressing either β-SpecSCA5.Scer\UAS or β-SpecSCA5.Scer\UAS.T:Lhem\EosFP-m3.2 under the control of Scer\GAL4elav.PU are near lethal.

β-Specem21/Y embryos show midline axon guidance defects, with medial longitudinal fascicles ectopically crossing the midline.

Expression of β-SpecΔPH.Ubi-p63E.T:Hsap\MYC in a β-Specem21 background rescues flies rarely. These rescued flies are strikingly small in size and are sterile.

Homozygotes fail to hatch (~90%) or die as early first instar larvae (~10%). Hatched larvae are lethargic and display limited movement. General anatomy of neuromusculature, epidermis, denticles and mouthparts is normal. Morphology of neuromuscular junction, and number of boutons on muscle 6/7 is normal. Mutants have severely reduced synaptic transmission. Evoked EJCs are reduced to approximately one quarter wild type values in voltage clamped muscles. Glutamate response is normal suggesting that the defect is presynaptic. Synaptic transmission is only insignificantly reduced during high-frequency stimulation. However the frequency of sEJCs and mEJCs are significantly reduced, suggesting a Ca2+-independent defect in synaptic vesicle fusion. The amplitude of mEJCs is unaffected, consistent with unaffected postsynaptic receptors. Distribution of active zones and synaptic vesicle clustering is normal. The distribution/polarization of synaptic proteins Syn, Csp, syt, Syx1A dlg1 is distinctly abnormal.

Most hemizygous male embryos die before hatching, although they appear to be fully developed and motile (22 +/- 6% hatch). The mutant larvae survive for 1-3 days, whether or not they hatch. Homozygous larvae show reduced midgut acidification compared to wild-type larvae.

External Data
Interactions
Show genetic interaction network for Enhancers & Suppressors
Phenotypic Class
Phenotype Manifest In
Additional Comments
Genetic Interactions
Statement
Reference
Xenogenetic Interactions
Statement
Reference
Complementation and Rescue Data
Images (0)
Mutant
Wild-type
Stocks (0)
Notes on Origin
Discoverer
External Crossreferences and Linkouts ( 0 )
Synonyms and Secondary IDs (3)
Reported As
Name Synonyms
Secondary FlyBase IDs
    References (6)