Open Close
General Information
Symbol
Dmel\mbcD11.2
Species
D. melanogaster
Name
FlyBase ID
FBal0063880
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:

G23792195A

Reported nucleotide change:

G?A

Amino acid change:

W97term | mbc-PA; W97term | mbc-PB

Reported amino acid change:

W97term

Comment:

TGG to TGA nonsense mutation in codon Trp97.

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

Nucleotide substitution: G?A.

Amino acid replacement: W97term.

Amino acid replacement: E97term.

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

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

mbcC1/mbcD11.2 transheterozygote embryos display defects in the migration of the visceral longitudinal muscle founder cells and their morphology as well as the muscle fusion. Late in the embryonic development, the first midgut constriction is missing in the mbcC1/mbcD11.2 mutants.

In homozygous mutant embryos, myoblasts are competent to migrate to the founder cells, but fusion does not occur.

Homozygous embryos exhibit breaks in the outer longitudinal fascicles and a collapse of axons onto the MP1 fascicle tracts. Thinning of the longitudinal axon tracts and abnormal spacing between segments is also observed.

Unfused myoblasts are apparent in stage 16 homozygous embryos. Although the majority of founder cells examined remain mononucleate, a limited amount of fusion does occur, as binucleate muscle precursors that have undergone a single fusion event between a founder cell and a fusion competent myoblast (FCM) are seen in the mutant embryos. The muscle founders analysed and the percentage of segments in which the founder cell remains mononucleate are as follows: DA1 (72.1%), DO1 (76.3%), LO1 (90.2%), LT2 (93.4%), LT4 (95.0%), VT1 (78.9%), VA2 (84.6%). The overall level of myoblast fusion in embryos lacking both maternal and zygotic function is roughly comparable to that seen in zygotic mutant embryos.

The F-actin foci which are seen in wild-type FCMs at points of contact with developing myofibers are less dense and somewhat dispersed in homozygous FCMs. In addition, the actin cytoskeletal network of the mutant FCMs is different from wild type, with many of the mutant cells showing a complete collapse of the network.

The eve-expressing DA1 founder cell undergoes no fusion in mbcD11.2 embryos.

Myoblast fusion is absent in mbcD11.2 zygotic mutant embryos and in embryos derived from mbcD11.2 germline clones.

The extent of myoblast fusion in mbcD11.2 mutant embryos is significantly reduced compared to wild type.

Homozygous embryos do not show any apparent defects in macrophage migration.

When mutant somatic clones are made in border cells, a strong effect is seen on border cell migration. At stage 10 only about 10% of mutant border cell clusters reach the oocyte.

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

mbcD11.2 is a suppressor of centripetally migrating follicle cell & actin filament phenotype of Pvrλ.UASp.Tag:MYC, Scer\GAL4slbo.2.6

Other
Additional Comments
Genetic Interactions
Statement
Reference

The presence of mbcD11.2/+ increases the severity of muscle attachment defects in msk4/msk5 embryos.

mbcD11.2/+ largely suppresses the muscle detachment phenotype of Scer\GAL4twi.PU mskScer\UAS.cLa embryos.

In mbcD11.2/mbcD11.2, spg2/spg2 double mutants, myoblasts fail to fuse but still cluster around the founder cells (as in mbcD11.2/mbcD11.2 mutants).

There is no significant increase in broken fascicles or the collapse of the outer longitudinal tracts in mbcD11.2, spg2 double mutants over mbcD11.2 mutants alone. However, there is an increase in midline fascicle crossing in the double mutants. Abnormal positioning of the ventral nerve cord is also observed in the double mutants.

mbcD11.2, Df(2L)CadNΔ14 embryos do not show increased axonal outgrowth or guidance defects compared to mbcD11.2 embryos.

Expression of Rac1V12.Scer\UAS under the control of Scer\GAL4sns.PK rescues myoblast fusion in homozygous mbcD11.2 embryos such that the somatic muscle pattern is almost wild type.

Expression of Rac1V12.Scer\UAS under the control of Scer\GAL4kirre-rP298 does not rescue myoblast fusion in homozygous mbcD11.2 embryos.

Expression of Rac1Scer\UAS.cLa under the control of Scer\GAL4sns.PK does not rescue myoblast fusion in homozygous mbcD11.2 embryos.

mbcD11.2 spg2 double mutant embryos have a roughly comparable overall level of myoblast fusion compared to mbcD11.2 single mutant embryos.

The rough eye phenotype resulting from Scer\GAL4GMR.PU-mediated expression of Ced-12Scer\UAS.cGa and mbcScer\UAS.cBa is suppressed by heterozygosity for mbcD11.2.

Xenogenetic Interactions
Statement
Reference
Complementation and Rescue Data
Rescued by
Comments

Expression of either mbcScer\UAS.T:Ivir\HA1 or mbcNPxxP.Δ1807.Scer\UAS.T:Ivir\HA1 under the control of Scer\GAL4sns.PK restores fusion in mbcD11.2 embryos and a wild-type somatic muscle pattern is formed.

Myoblast fusion remains severely impaired in mbcD11.2 embryos expressing mbcScer\UAS.T:Ivir\HA1 under the control of Scer\GAL4kirre-rP298. These embryos show a roughly twofold increase in muscle precursor formation (where a single fusion event between a founder cell and a fusion competent myoblast has occurred) compared to mbcD11.2 embryos.

Expression of mbcScer\UAS.T:Ivir\HA1 rescues the myoblast fusion defect in mbcD11.2 embryos when expressed using Scer\GAL4twi.PG or Scer\GAL4how-24B but not Scer\GAL4kirre-rP298.

Scer\GAL4twi.PG-mediated expression of mbcSH3W47K.Scer\UAS.T:Ivir\HA1 fails to rescue the mbcD11.2 myoblast fusion defect.

Scer\GAL4twi.PG-mediated expression of mbcDockerF6.4.Scer\UAS.T:Ivir\HA1 fails to rescue the mbcD11.2 myoblast fusion defect.

Scer\GAL4twi.PG- or Scer\GAL4how-24B-mediated expression of mbcCBS.Scer\UAS rescues the mbcD11.2 myoblast fusion defect.

Scer\GAL4twi.PG- or Scer\GAL4how-24B-mediated expression of mbcΔ1807.Scer\UAS.T:Ivir\HA1 rescues the mbcD11.2 myoblast fusion defect.

Scer\GAL4twi.PG- or Scer\GAL4how-24B-mediated expression of mbcNPxxP.Scer\UAS.T:Ivir\HA1 rescues the mbcD11.2 myoblast fusion defect.

Scer\GAL4twi.PG- or Scer\GAL4how-24B-mediated expression of mbcNPxxP.Δ1807.Scer\UAS.T:Ivir\HA1 rescues the mbcD11.2 myoblast fusion defect.

Scer\GAL4twi.PG- or Scer\GAL4how-24B-mediated expression of mbcΔPRM.Scer\UAS.T:Ivir\HA1 rescues the mbcD11.2 myoblast fusion defect.

Scer\GAL4twi.PG- or Scer\GAL4how-24B-mediated expression of mbcΔDHR1.Scer\UAS.T:Ivir\HA1 fails to rescue the mbcD11.2 myoblast fusion defect.

Images (0)
Mutant
Wild-type
Stocks (5)
Notes on Origin
Discoverer
External Crossreferences and Linkouts ( 0 )
Synonyms and Secondary IDs (6)
References (23)