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General Information
Symbol
Dmel\Lar2127
Species
D. melanogaster
Name
FlyBase ID
FBal0128174
Feature type
allele
Associated gene
Associated Insertion(s)
Carried in Construct
Key Links
Nature of the Allele
Mutations Mapped to the Genome
 
Type
Location
Additional Notes
References
Nucleotide change:

G19726369A

Reported nucleotide change:

G?A

Amino acid change:

W834term | Lar-PA; W816term | Lar-PB; W717term | Lar-PD; W837term | Lar-PF; W740term | Lar-PG; W732term | Lar-PH; W746term | Lar-PI

Reported amino acid change:

W834term

Comment:

G to A nucleotide change at the second or third position of the wild type Trp codon leads to a nonsense mutation (exact site of mutation unspecified). The mutation was annotated at the second base of the codon.

Associated Sequence Data
DNA sequence
Protein sequence
 
 
Progenitor genotype
Cytology
Nature of the lesion
Statement
Reference

Amino acid replacement: W834term.

Nucleotide substitution: G?A.

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

Lar2127 homozygous MARCM clones of R7 photoreceptor neurons at 40-60 percent through pupal development (P40-60) have significantly reduced lifespan of bulbous growth cone filopodia (bulbs) at axon terminals, with no change in the number of transient bulbs, but significantly fewer stable bulbs and total bulbs, compared to controls, with no effect on other filopodia; unlike controls there are many timepoints during P60 where no bulbs are present; axons begin to retract at P40 and most are retracted by P70, unlike controls, which do not retract.

In LarC12/Lar2127 mutants, many R7 axons are mis-targeted in the retina.

Axon terminals of homozygous R7 photoreceptor cell clones often fail to contact the M6 layer of the medulla.

Most R7 photoreceptor axons terminate at the more superficial R8 layer in LarC12/Lar2127 mutant eye discs.

Reduced synaptic growth at the neuromuscular junction is observed in LarC12/Lar2127 mutant third instar larvae.

57% of pupal R1-R6 axons mutant for Lar2127 do not extend their axons, or show aberrant axon extension, targeting, and morphology.

Pupal R4 axons frequently fail to extend, or extend aberrantly when mutant for Lar2127.

Using MARCM, Lar2127 mutant lamina neurons do not show mistargeting phenotypes in lamina cells L1-L5, whilst 95% of mutant R7 cells show mistargeting.

Lar2127 mutants exhibit a specific pattern of disruption in the structure of the cartridge, the synaptic unit in the lamina. Some cartridges have either >6 or <6 R cells axons, and some adjacent cartridges fuse.

In Lar2127 mutants, R7 axons frequently stop at abnormally distal positions within the R8 recipient layer, leaving gaps in the array of otherwise regular R7 termini. However the ganglion-specific targeting of R1-R6 axons to the lamina nor the layer-specific targeting of R8 axons within the medulla are affected.

Lar2127/LarC12 mutants exhibit aberrant R7 photoreceptor targeting, where approximately 15% of R7 axons project beyond the R8 layer. R1-R6 targeting is as wild-type.

In Lar2127/Larbypass mutants, wild-type targeting of R7 photoreceptor cells occurs in approximately 20% of cases.

Stage 14 oocytes from Lar2127/LarC12 mutants are defective in egg elongation in 30% of cases.

Stage 14 oocytes from Lar2127/Larbypass females are indistinguishable from wild-type.

Lar2127 R7 axons (analysed as single cell mutant clones) target correctly in the medulla at both 17% and 35% APF, although some growth cones have a collapsed morphology.

Mosaic flies in which the photoreceptor cells are homozygous show defects in the optomotor response (75% fail to respond to a motion stimulus) and the UV/visual light choice test (69% show phototaxis towards visible light, compared to only 12% of wild-type flies). 74% of single homozygous R7 photoreceptor cells in the lamina (induced in a heterozygous background) fail to terminate at their normal target layer. Mosaic animals in which the whole eye is homozygous show 81% mistargeted R7 axons.

Homozygous clones in the eye contain the normal arrangement of photoreceptors. R7 growth cones extend beyond the R8 termini in Lar2127/Lar5.5 animals 15 hours after pupariation as occurs in wild type, although the R7 growth cones have a compact, club-like shape instead of the normal expanded morphology. Only 52.9% of Lar2127/Lar5.5 R7 axons select their correct target layer.

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

Lar2127/Lar[+] is a suppressor | partially of lethal phenotype of Liprin-αE/Liprin-α1

Lar2127/Lar[+] is a suppressor | partially of lethal phenotype of Liprin-αF/Liprin-αE

Other
Statement
Reference
Phenotype Manifest In
Enhanced by
Statement
Reference

Lar5.5/Lar2127 has photoreceptor cell R7 & axon phenotype, enhanceable by ena[+]/enaGC1

Lar5.5/Lar2127 has photoreceptor cell R7 & axon phenotype, enhanceable by trio1/trio[+]

Suppressed by
Additional Comments
Genetic Interactions
Statement
Reference

bdlEX2/+ significantly increases the number of correctly targeted R7 axons in LarC12/Lar2127 mutants.

Expression of either trioScer\UAS.cBa or RhoGAP100FScer\UAS.T:Zzzz\FLAG under the control of Scer\GAL4Act.PU in Lar2127 R7 photoreceptor cell clones partially suppresses the failure of the axon terminals to contact the M6 layer of the medulla.

Expression of CadNScer\UAS.cIa under the control of Scer\GAL4elav-C155 in Lar2127 somatic mutant clones enhances the photoreceptor targeting defects observed in single mutants.

When large clones of cells mutant for both Lar2127 and CadNΔ14 are generated in the eye, R4 axon targeting errors are more frequently observed than in single mutants.

When large clones of cells mutant for both Liprin-αE and Lar2127 are generated in the eye, R4 axon targeting errors are more frequently observed than in single mutants.

When large clones of cells mutant for Liprin-αE, Lar2127, and CadNΔ14 are generated in the eye, R4 axon targeting errors are observed, but the frequency of defects is similar to Liprin-αE; Lar2127, Lar2127; CadNΔ14, or Liprin-αE; CadNΔ14 double mutant combinations.

Overexpression of Liprin-αScer\UAS.T:Ivir\HA1 under the control of Scer\GAL4elav-C155 or Scer\GAL4GMR.PF in a Lar2127/LarC12 mutant background partially restores R7 targeting.

CadN405 Lar2127 double mutant R7 growth cones show similar phenotypes to CadN405 single mutant R7 growth cones.

Xenogenetic Interactions
Statement
Reference
Complementation and Rescue Data
Comments

Expression of LarScer\UAS.T:Ivir\HA1, LarC1638S.Scer\UAS, LarC1929S.Scer\UAS, LarCSX2.Scer\UAS, LarD1YLCS.Scer\UAS, LarΔIg123.Scer\UAS, LarΔFn123.Scer\UAS, LarΔFn456.Scer\UAS, or LarΔIg123ΔFn1-6.Scer\UAS.T:wg,T:Ivir\HA1 under the control of Scer\GAL4elav-C155 in LarC12/Lar2127 mutant eye discs rescues axon mistargeting. Expression of LarPPLL.Scer\UAS or LarPPLL.D1CS.Scer\UAS only partially rescues the axon targeting phenotype. Expression of LarΔFn789.Scer\UAS or LarΔFn2-9.Scer\UAS fails to rescue the axon targeting phenotype.

Expression of LarScer\UAS.T:Ivir\HA1 or LarPPLL.Scer\UAS under the control of Scer\GAL4elav-C155 in LarC12/Lar2127 mutant third instar larvae rescues synaptic growth at the neuromuscular junction. Expression of LarC1638S.Scer\UAS, LarD1YLCS.Scer\UAS, or LarCSX2.Scer\UAS only partially rescues this phenotype.

Expression of LarScer\UAS.cKa under the control of Scer\GAL4elav-C155 almost completely rescues the aberrant axon extension in Lar2127 mutant photoreceptor cells.

Expression of LarCSX2.Scer\UAS under the control of Scer\GAL4elav-C155 almost completely rescues the aberrant axon extension in Lar2127 mutant photoreceptor cells.

Expression of LarC1929S.Scer\UAS under the control of Scer\GAL4elav-C155 completely rescues the aberrant axon extension in Lar2127 mutant photoreceptor cells.

Expression of LarΔIg123.Scer\UAS under the control of Scer\GAL4elav-C155 partially rescues the aberrant axon extension in Lar2127 mutant photoreceptor cells.

Expression of LarΔFn2-9.Scer\UAS under the control of Scer\GAL4elav-C155 partially rescues the aberrant axon extension in Lar2127 mutant photoreceptor cells.

Expression of LarScer\UAS.T:Ivir\HA1 under the control of Scer\GAL4elav-C155 rescues R7 targeting in Lar2127/LarC12 mutants.

Expression of LarScer\UAS.T:Ivir\HA1 under the control of Scer\GAL4elav-C155 fails to rescue R7 targeting in Lar2127/LarC12 mutants.

Expression of LarScer\UAS.T:Ivir\HA1 under the control of Scer\GAL4T155 rescues the egg elongation phenotype observed in stage 14 oocytes from Lar2127/LarC12 mutants.

Expression of LarΔC.Scer\UAS.T:wg,T:Ivir\HA1 under the control of Scer\GAL4T155 fails to rescue the egg elongation phenotype observed in stage 14 oocytes from Lar2127/LarC12 mutants and indeed exacerbates the phenotype, with approximately 44% of the oocytes displaying a 'rounded phenotype', compared to approximately 30% in the Lar2127/LarC12 mutant.

Images (0)
Mutant
Wild-type
Stocks (1)
Notes on Origin
Discoverer

Selected as: a mutation that results in photoreceptor projection defects in mosaic animals in which the retina, but no other tissue is homozygous.

External Crossreferences and Linkouts ( 0 )
Synonyms and Secondary IDs (5)
References (15)