FlyBase Allele Report: Dmel\Syx1A[3-69]

General Information

Symbol

Dmel\Syx1A^3-69

Species

D. melanogaster

Name

FlyBase ID

FBal0092503

Feature type

allele

Associated gene

Dmel\Syx1A

Associated Insertion(s)

Carried in Construct

Also Known As

syx^3-69

Key Links

Genomic Maps

JBrowse

Allele class

Mutagen

ethyl methanesulfonate

Nature of the Allele

Allele class

Mutagen

ethyl methanesulfonate

(Littleton et al., 1998)

Progenitor genotype

Cytology

Description

Nucleotide substitution: C?T.

(Lagow et al., 2007, Littleton et al., 1998)

Amino acid replacement: T254I.

(Lagow et al., 2007, Littleton et al., 1998)

The T254I mutation lies in the 'a' position on the hydrophobic face of a heptad repeat at the end of the third coiled coil motif of the Syx1A protein, the H3 domain, three amino acids upstream of the C. botulinum C cleavage site.

(Littleton et al., 1998)

Mutations Mapped to the Genome

Curation Data

Type

Location

Additional Notes

References

point_mutation

3R:24,103,683..24,103,683 [-]

Nucleotide change:

C24103683T

Reported nucleotide change:

C?T

Amino acid change:

T254I | Syx1A-PA; T254I | Syx1A-PB; T254I | Syx1A-PC

Reported amino acid change:

T254I

(Littleton et al., 1998)

Variant Molecular Consequences

Associated Sequence Data

DDBJ / EMBL / GenBank

DNA sequence

Protein sequence

UniProtKB/Swiss-Prot

UniProtKB/TrEMBL

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

neuromuscular junction | third instar larval stage

(Cho et al., 2015)

NMJ bouton | third instar larval stage

(Cho et al., 2015)

optic cartridge & synaptic vesicle

(Littleton et al., 1998)

retina

(Littleton et al., 1998)

Detailed Description

Statement

Reference

Syx1A^3-69/Syx1A^3-69 homozygous larvae show significant increase in the frequency of spontaneous miniature excitatory postsynaptic currents (mESPCs) at the neuromuscular junction but their amplitude and area are not significantly different from wild-type controls. The amplitude and area of evoked postsynaptic currents are significantly increased regardless of Ca[2+] concentration (tested at 0.25, 1 and 2 mM Ca[2+])

(Vasin et al., 2016)

Syx1A^3-69 mutant third instar larvae display increased frequency of mini excitatory junction potentials (~spontaneous releases) as well as synaptic overgrowth (increased number of boutons) at neuromuscular junctions.

(Cho et al., 2015)

Syx1A^3-69 homozygous mutants show similar levels of synaptic vesicle endocytosis at the larval neuromuscular junction compared to control animals at both 25[o]C and 37[o]C.

(Vijayakrishnan et al., 2009)

Syx1A^3-69 mutant flies are rapidly paralysed at 38^oC but recover within 3 minutes when returned to a permissive temperature after a 20 minute period of paralysis. While Syx1A^3-69 mutant flies are paralysed at 38^oC, they are not motionless, they constantly shake their legs and abdomens.

Repetitive and phase-locked leg shaking is easily observed in Syx1A^3-69 flies at both the permissive temperature (20^oC) and the restrictive temperature (38^oC) following artificial stimulus of the giant fiber neuron.

The synaptic response of the dorsal longitudinal indirect flight muscles from Syx1A^3-69 flies is maintained at 38^oC. During observations, the intracellular electrodes are often dislodged from the dorsal longitudinal indirect flight muscles only from Syx1A^3-69 flies, along with a high incidence of spontaneous action potentials in the mutant muscles, indicating that synaptic transmission is not blocked at restrictive temperatures in Syx1A^3-69 flies. Light-induced 'on' and 'off' transient potentials of electroretinograms are not blocked by exposure of the Syx1A^3-69 fly to the restrictive temperature. In fact, the 'on' transient potential is slightly increased in amplitude at 38^oC.

The average amount of 7S SNARE complex is significantly increased in Syx1A^3-69 mutants compared to wild-type, at 22^oC. Similarly, the level of SNARE multimers is also significantly increased in the mutant.

The frequency of constitutive (or spontaneous) release of miniature excitatory postsynaptic potentials (mEPSPs) from third instar larval body-wall muscles innervated by motoneurons is dramatically increased some 7-fold in Syx1A^3-69 flies, compared to the wild-type. The average mini amplitude is similar in both the Syx1A^3-69 mutant and the wild-type larvae, suggesting that quanta and postsynaptic receptors likely remain normal. The unusually high rate of spontaneous release remains in the Syx1A^3-69 mutant in the absence of extracellualr Ca²⁺, although the resting potential is no different to wild-type. The mini frequency remains 13-fold higher in Syx1A^3-69 mutants compared to the wild-type in Ca²⁺-free saline containing the membrane-permeable Ca²⁺ chelator EGTA-AM. The amplitude of evoked EPSPs is significantly increased to 37mV in the Syx1A^3-69 mutant from 25mV in the wild-type. Because the average mini amplitude is not significantly different between the mutant and the wild-type, this increase in EPSP amplitude most likely reflects an enhancement in presynaptic release. There is a 2-fold increase in quantal content in the mutant compared to the wild-type. Syx1A^3-69 mutants do no exhibit a detectable difference in synaptic vesicle recycling compared to wild-type.

The resting potential of the muscle fiber in Syx1A^3-69/+ and Syx1A^3-69/Syx1A^3-69 mutants is not significantly different from that in the wild-type. In Syx1A^3-69/+ mutants the frequency of spontaneous fusion is significantly higher than that in the wild-type, but much lower than that in the homozygote. The amplitude of evoked EPSPs in Syx1A^3-69/+ mutants is similar to that in homozygotes, but significantly higher than that in the wild-type.

In Syx1A^3-69/Syx1A^Δ229 mutants, the mini-frequency is 22.3Hz, which is significantly higher than in the wild-type larvae. At 0.8mM Ca²⁺, the evoked EPSP amplitude is significantly increased to 37.9mV from 29.5mV in the wild-type larvae. These results are similar to those found in Syx1A^3-69 homozygotes.

Neuronal expression of Syx1A^Scer\UAS.cBa under the control of Scer\GAL4^elav-C155 in Syx1A^3-69/Syx1A^Δ229 results in a dramatic reduction in the frequency of constitutive secretion to 8.8Hz from 24.9Hz. The average amplitude of EPSPs is also significantly reduced in Syx1A^3-69/Syx1A^Δ229 mutants expressing Syx1A^Scer\UAS.cBa under the control of Scer\GAL4^elav-C155. This EPSP amplitude is similar to that in Syx1A^Scer\UAS.cBa/Scer\GAL4^elav-C155 flies, but significantly higher than wild-type.

(Lagow et al., 2007)

After 10 minutes at 33^oC, Syx1A^3-69 homozygotes display only approximately 10% paralysis. Paralysed Syx1A^3-69 flies completely recover to an upright position within 1-2 minutes after returning to room temperature.

(Huang et al., 2006)

Heterozygous flies lose coordination as the temperature is raised, such that at 39^oC, they display a "bottom-dwelling" phenotype when placed in glass test tubes, in contrast to wild-type flies at this temperature, which are able to run up and down the sides of the tube for several minutes before also becoming uncoordinated. Homozygotes "pass out" completely in seconds at 39^oC.

(van Swinderen and Greenspan, 2005)

In ERG assay, mutants lose the on/off transients at 38^oC. Recovery of transients at 20^oC is rapid. Paralysis occurs after temperature shift to 38^oC. Kinetics of onset of paralysis are quicker for homozygotes than for heterozygotes. ERG phenotypes correlate with paralytic phenotypes: time course of paralysis and recovery for Syx1A mutants is more rapid than for comt mutants. Ultrastructural studies reveal that the number of synaptic vesicles in photoreceptor terminals in the optic cartridge is dramatically increased. Clear increases occur in the number of vesicles clustered round T-bars. Number of docked vesicles is increased compared to wild type.

(Littleton et al., 1998)

External Data

Linkouts

Interactions

Show genetic interaction network for Enhancers & Suppressors

Phenotypic Class

Enhanced by

Statement

Reference

Syx1A^3-69 has paralytic | heat sensitive phenotype, enhanceable by stmA¹

(Huang et al., 2006)

Syx1A^3-69 has paralytic | heat sensitive phenotype, enhanceable by stmA[+]/stmA¹

(Huang et al., 2006)

Suppressed by

Statement

Reference

Syx1A^3-69 has uncoordinated | dominant | heat sensitive phenotype, suppressible by Act42A[+]/Act42A^EP2096

(van Swinderen and Greenspan, 2005)

Syx1A^3-69 has uncoordinated | dominant | heat sensitive phenotype, suppressible by Gmd^EP315/Gmd[+]

(van Swinderen and Greenspan, 2005)

Syx1A^3-69 has uncoordinated | dominant | heat sensitive phenotype, suppressible by MESR4[+]/MESR4^EP386

(van Swinderen and Greenspan, 2005)

Syx1A^3-69 has uncoordinated | dominant | heat sensitive phenotype, suppressible by Pdk[+]/Pdk^EP547

(van Swinderen and Greenspan, 2005)

Syx1A^3-69 has uncoordinated | dominant | heat sensitive phenotype, suppressible by RpS23[+]/RpS23^EP638

(van Swinderen and Greenspan, 2005)

Syx1A^3-69 has uncoordinated | dominant | heat sensitive phenotype, suppressible by aop^EP598/aop[+]

(van Swinderen and Greenspan, 2005)

Syx1A^3-69 has uncoordinated | dominant | heat sensitive phenotype, suppressible by kis^EP563/kis[+]

(van Swinderen and Greenspan, 2005)

Syx1A^3-69 has uncoordinated | dominant | heat sensitive phenotype, suppressible by EP2[+]/EP2^EP2

(van Swinderen and Greenspan, 2005)

Syx1A^3-69 has uncoordinated | dominant | heat sensitive phenotype, suppressible by CG3760^EP548/CG3760[+]

(van Swinderen and Greenspan, 2005)

Syx1A^3-69 has uncoordinated | dominant | heat sensitive phenotype, suppressible by Etl1^EP701/CG5899[+]

(van Swinderen and Greenspan, 2005)

Syx1A^3-69 has uncoordinated | dominant | heat sensitive phenotype, suppressible by CG9894[+]/Bacc^EP7

(van Swinderen and Greenspan, 2005)

Syx1A^3-69 has uncoordinated | dominant | heat sensitive phenotype, suppressible by EP1244^EP1244/EP1244[+]

(van Swinderen and Greenspan, 2005)

Syx1A^3-69 has uncoordinated | dominant | heat sensitive phenotype, suppressible by EP364[+]/EP364^EP364

(van Swinderen and Greenspan, 2005)

Syx1A^3-69 has uncoordinated | dominant | heat sensitive phenotype, suppressible by EP454[+]/EP454^EP454

(van Swinderen and Greenspan, 2005)

Syx1A^3-69 has uncoordinated | dominant | heat sensitive phenotype, suppressible by EP704^EP704/EP704[+]

(van Swinderen and Greenspan, 2005)

Syx1A^3-69 has uncoordinated | dominant | heat sensitive phenotype, suppressible by EP718[+]/EP718^EP718

(van Swinderen and Greenspan, 2005)

NOT suppressed by

Statement

Reference

Syx1A^3-69 has abnormal neurophysiology | third instar larval stage phenotype, non-suppressible by Syt4^BA1/Syt4^BA1

(Cho et al., 2015)

Enhancer of

Statement

Reference

Syx1A^3-69 is an enhancer of paralytic | heat sensitive phenotype of stmA¹

(Huang et al., 2006)

Phenotype Manifest In

Suppressed by

Statement

Reference

Syx1A^3-69 has neuromuscular junction | third instar larval stage phenotype, suppressible by Syt4^BA1/Syt4^BA1

(Cho et al., 2015)

Syx1A^3-69 has NMJ bouton | third instar larval stage phenotype, suppressible by Syt4^BA1/Syt4^BA1

(Cho et al., 2015)

Other

Statement

Reference

Syx1A^3-69, stmA¹ has NMJ bouton | larval stage | temperature conditional phenotype

(Vijayakrishnan et al., 2009)

Syx1A^3-69, stmA¹ has garland cell | wandering third instar larval stage | temperature conditional phenotype

(Vijayakrishnan et al., 2009)

Additional Comments

Genetic Interactions

Statement

Reference

Simultaneous expression of cpx^E34A.UAS.7A and nSyb^K83A.UAS under the control of Scer\GAL4^elav-C155 results in a significant decrease in the frequency of miniature excitatory postsynaptic currents, mESPCs, at the larval neuromuscular junction compared to larvae expressing cpx^UAS.7A with nSyb^UAS.cLa, but the magnitude of this reduction is comparable to that observed for either cpx^E34A.UAS.7A or nSyb^K83A.UAS relative to their counterpart wild-type transgene-overexpressing controls.

(Vasin et al., 2016)

The synaptic overgrowth (increased number of boutons) at neuromuscular junctions observed in third instar larvae mutant for Syx1A^3-69 can be suppressed by homozygosity of Syt4^BA1 (which on its own does not lead to any elevation in synaptic growth) but this fails to suppress the increased frequency of mini excitatory junction potentials.

(Cho et al., 2015)

stmA¹; Syx1A^3-69 double mutants show a strong reduction in synaptic vesicle endocytosis at the larval neuromuscular junction compared to control animals at both 25[o]C and 37[o]C.

stmA¹; Syx1A^3-69 double mutants show endocytosis activity in garland cells at 25[o]C. At 37[o]C no endocytosis is observed.

(Vijayakrishnan et al., 2009)

stmA¹; Syx1A^3-69 double mutants rapidly paralyse at 33^oC, with approximately 90% of mutants completely paralysed within 10 minutes. Approximately 5 minutes are required for all paralysed stmA¹; Syx1A^3-69 double mutants to regain an upright position after return to room temperature.

stmA¹/stmA¹; Syx1A^3-69/Syx1A^3-69 homozygotes and stmA¹/stmA^rev499; Syx1A^3-69/Syx1A^3-69 double mutants exhibit an indistinguishable synergistic genetic interaction.

(Huang et al., 2006)

Xenogenetic Interactions

Statement

Reference

Complementation and Rescue Data

Fails to complement

Syx1A^Δ229

(Littleton et al., 1998)

Rescued by

Syx1A^3-69 is rescued by Syx1A^+t13

(Littleton et al., 1998)

Partially rescued by

Syx1A^Δ229/Syx1A^3-69 is partially rescued by Scer\GAL4^elav-C155/Syx1A^UAS.cBa

(Lagow et al., 2007)

Comments

Images (0)

Mutant

Wild-type

Stocks (0)

Notes on Origin

Discoverer

External Crossreferences and Linkouts ( 0 )

Synonyms and Secondary IDs (5)

Reported As

Symbol Synonym

Syx1A^3-69

syx1A^3-69

syx^3-69

(Vasin et al., 2016, Cho et al., 2015, Barber et al., 2009, Vijayakrishnan et al., 2009, Lagow et al., 2007, Huang et al., 2006, Montana and Littleton, 2001, Littleton et al., 1998)

ts^3-69

(Littleton et al., 1998)

Name Synonyms

syntaxin3-69

(Vijayakrishnan et al., 2009)

Secondary FlyBase IDs

References (9)

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