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General Information
Symbol
Dmel\HemJ4-48
Species
D. melanogaster
Name
FlyBase ID
FBal0105155
Feature type
allele
Associated gene
Associated Insertion(s)
Carried in Construct
Also Known As
ketteJ4-48, ketteJ4-048
Key Links
Nature of the Allele
Mutations Mapped to the Genome
 
Type
Location
Additional Notes
References
Nucleotide change:

G22286454A

Amino acid change:

W490term | Hem-PA

Reported amino acid change:

W490term

Comment:

G to A nucleotide change at the second or third position of the Trp codon leads to a nonsense mutation. (exact site of mutation unspecified). Site of nucleic acid difference in mutant inferred by FlyBase based on reported amino acid change.

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

Amino acid replacement: W490term.

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

Bouton numbers are unaffected at the NMJ of HemJ4-48/+ third instar larvae.

Mutant stage 16 embryos show a severe myoblast fusion defect in the dorsal pharyngeal muscle.

HemJ4-48/HemG1-37 transheterozygote embryos display defects in the number, migration and morphology of visceral longitudinal muscle founder cells.

Defects in longitudinal muscle fusion are observed in HemJ4-48 mutant embryos: mainly mononucleated and only a few binucleated muscle cells are found at late embryonic stages.

Approximately 13% ofHemJ4-48 mutant embryos display a duplication of the RP2 neuron in one hemisegment and have one missing in the contralateral segment. The GMC is formed correctly in both hemisegments and divides normally into an RP2 and a sib cell. The RP2 duplication occurs due to aberrant crossing of the midline at 11hr of development. The sib cell remains in the correct hemisegment. In 4% of HemJ4-48 embryos the RP2 neurons fail to migrate and are found in the position of a newly formed GMC-1. No axon projections are seen in these cells. The axonal projections in the mis-migrated RP2 cells have a contra-ipsilateral axon projection, fasciculating correctly with the intersegmental nerve bundle. No defects are seen in the commissural tracts.

HemJ4-48/HemC3-20 mutant embryos have a duplication of the RP2 neuron in one hemisegment and have one missing in the contralateral segment.

HemJ4-48/Df(3L)ED230 mutant embryos have a duplication of the RP2 neuron in one hemisegment and have one missing in the contralateral segment.

17% of embryos expressing HemScer\UAS.ΔJ4-48 under the control of Scer\GAL4nos.UTR.T:Hsim\VP16 in a HemJ4-48/Df(3L)ED230 mutant background display an RP2 neuron defect in which a duplication is seen in one hemisegment and have one missing in the contralateral segment. The GMC is formed in both hemisegments and divides normally into an RP2 and a sib cell. The RP2 duplication occurs due to aberrant crossing of the midline at 11hr of development. The sib cell remains in the correct hemisegment.

HemJ4-48 mutants exhibit normal visceral mesoderm development, resulting in normal gut development.

Stage 15 HemJ4-48 mutant embryos contain enlarged F-actin foci. These actin foci are found in fusion competent myoblasts (FCMs), but are not seen in founder cells. The percentage of invasive foci and depth of invasion are both comparable to wild type. Myoblast fusion is blocked before fusion pore formation as cytoplasmic material exchange does not occur between the founder cell and FCM.

HemJ4-48 mutants show enlarged foci, as well as increased numbers of actin foci. Enlarged foci are seen in these mutants from the earliest stages of fusion and foci persist after fusion would be complete in wild-type.

Homozygous HemJ4-48 mutant embryos exhibit a myoblast fusion phenotype.

HemJ4-48/HemΔ2-6 larvae have reduced neuromuscular junctions with bulging, irregular boutons. About 15% of the heads of HemJ4-48/HemΔ2-6 flies have one or more bent macrochaetae.

HemJ4-48 mutant embryos contain many unfused myoblasts, even at stage 16, which cluster close to stretched mini-muscles. Marker analysis indicates that both founder cells and fusion competent myoblasts form normally at stage 13 in these embryos. By stage 14 mini-muscles with 3-4 nuclei are apparent at the site of the developing DA1 and DO1 muscles. As in wild-type, these 3-4 nuclei precursor cells establish contacts with fusion-competent myoblasts and plaques form at the sites of contact. Unlike wild-type, there is no sign of membrane breakdown in the vicinity of these plaques which remain visible into stage 15. Further fusion fails to occur. By contrast stage 15-16 wild type DA1 contains up to 14 nuclei. Dorsal closure is normal in HemJ4-48 mutant embryos, as is formation of the dorsal vessel and cardioblasts.

Commissures are fused in stage 16 mutant embryos, and the two longitudinal connectives are closer to the midline than in normal embryos.

External Data
Interactions
Show genetic interaction network for Enhancers & Suppressors
Phenotypic Class
Enhanced by
Statement
Reference
Suppressed by
Enhancer of
Statement
Reference
NOT Enhancer of
Statement
Reference

Hem[+]/HemJ4-48 is a non-enhancer of lethal | embryonic stage phenotype of WASp3D3-035

NOT Suppressor of
Statement
Reference

Hem[+]/HemJ4-48 is a non-suppressor of lethal | embryonic stage phenotype of WASp3D3-035

Other
Phenotype Manifest In
Enhanced by
Statement
Reference
NOT Enhanced by
Statement
Reference

HemJ4-48 has embryonic myoblast phenotype, non-enhanceable by WASp3D3-035

Suppressed by
Enhancer of
Statement
Reference
NOT Enhancer of
Statement
Reference

Hem[+]/HemJ4-48 is a non-enhancer of embryonic myoblast phenotype of WASp3D3-035

Hem[+]/HemJ4-48 is a non-enhancer of muscle attachment site phenotype of WASp3D3-035

NOT Suppressor of
Statement
Reference

Hem[+]/HemJ4-48 is a non-suppressor of embryonic myoblast phenotype of WASp3D3-035

Hem[+]/HemJ4-48 is a non-suppressor of muscle attachment site phenotype of WASp3D3-035

Other
Additional Comments
Genetic Interactions
Statement
Reference

Expression of psidinScer\UAS.cKa under the control of Scer\GAL4slbo.2.6 in a HemJ4-48 heterozygous background has little or no effect on border cell migration.

Abl2 HemJ4-48 double mutant embryos show a stronger RP2 neuron migration defect compared to either single mutant. Approximately 17% of embryos display a duplication of the RP2 neuron in one hemisegment and have one missing in the contralateral segment.

Expression of SCARScer\UAS.P\T.cZa under the control of Scer\GAL4sca.PU suppresses the RP2 neuron migration defects seen in HemJ4-48 mutant embryos.

Embryos double mutant for insc22 and HemJ4-48 display hemisegments containing 4 RP2 neurons and no sib cells. No RP2 or sib cells are found in the contralateral hemisegment.

Embryos double mutant for insc22 and HemJ4-48 display hemisegments containing two sib neurons and no RP2 neurons.

Expression of Act5CScer\UAS.P\T.T:Avic\GFP in HemJ4-48 mutant founder cells under the control of Scer\GAL4kirre-rP298 does not result in production of actin enriched structures on the membrane.

HemJ4-48/WASp3D3-035 double mutants exhibit a similar myoblast fusion phenotype as HemJ4-48 single mutants. A HemJ4-48 heterozygous background does not influence the WASp3D3-035 homozygous mutant phenotype. A WASp3D3-035 heterozygous background partially suppresses the block of fusion observed in HemJ4-48 homozygous mutants.

The short and split microchaetae phenotype of Sra-1Scer\UAS.T:Myr1; Scer\GAL4sca.PC flies unaffected by HemJ4-48/+.

The HemJ4-48 mutant phenotype is partially rescued by expression of Rac1V12.Scer\UAS under the control of Scer\GAL4sim.PS; the longitudinal connectives appear further apart and the commissures appear separated. VUM neurons are often seen projecting normally at the midline.

Xenogenetic Interactions
Statement
Reference
Complementation and Rescue Data
Fails to complement
Partially rescued by
Comments

The loss of muscle fusion seen in HemJ4-48 mutant embryos is almost completely rescued by HemScer\UAS.cHa; Scer\GAL4twi.PG.

HemScer\UAS.cHa partially rescues the HemJ4-48 phenotype when expressed under the control of Scer\GAL4sim.PS; commissures are separated and connectives are at a further distance from the midline compared to non-rescued HemJ4-48 embryos. The VUM neurons show a normal projection pattern.

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

Allelic series based on mutant phenotype; HemC3-20 = HemJ4-48 > HemP168 > HemG1-37 > HemJ1-70.

External Crossreferences and Linkouts ( 0 )
Synonyms and Secondary IDs (3)
References (19)