Open Close
General Information
Symbol
Dmel\Mer4
Species
D. melanogaster
Name
FlyBase ID
FBal0061731
Feature type
allele
Associated gene
Associated Insertion(s)
Carried in Construct
Nature of the Allele
Mutations Mapped to the Genome
 
Type
Location
Additional Notes
References
point mutation
Nucleotide change:

C19692450T

Amino acid change:

Q170term | Mer-PA; Q170term | Mer-PB

Reported amino acid change:

Q170term

Comment:

Site of nucleotide substitution 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: Q170term.

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 ( 1 )
Comments on Models/Modifiers Based on Experimental Evidence ( 0 )
 
Phenotypic Data
Phenotypic Class
Phenotype Manifest In
Detailed Description
Statement
Reference

Mer4 homozygous mutant embryos do not display any significant increase in the frequency of hemisegments with abnormal number of neurons in the asymmetrically dividing RP2 neural lineage.

Eyes homozygous for Mer4 (generated using the eyFLP method) show overgrowth compared to controls.

Eyes that are partially homozygous for Mer4 (generated using the eyFLP method without cell lethal) show mild overgrowth compared to controls.

Pupal retinae composed of homozygous Mer4 mutant cells show an increase in the number of interommatidial cells.

A few hemizygotes survive to the pharate adult stage. These males show an abnormality in nuclear grouping in elongating spermatid cysts, with the nuclei either being arranged in two groups or scattered.

Mutant spermatids at the late stage of spermatid elongation frequently contain two paracrystalline bodies within the major mitochondrial derivative compared to one in control cysts. Mutant spermatids are grossly disorganized compared to control cysts, which display cell-cell contact. Excessive cytoplasmic fragments are seen in mutant cysts.

The paired arrangement of axoneme with mitochondrial derivatives is often lost in individualisation stage spermatids. Mutant spermatids with multiple paracrystalline body-filled derivatives but with no axoneme, or with two axonemes are seen. Mutant cysts show cytoplasmic fragmentation together with condensed cytoplasmic remnants and gigantic cytoplasmic bodies.

Mutant cysts show normal 9+2 microtubule formation of the axoneme structure.

Females heterozygous for Mer4 do not show any chromosome nondisjunction and chromosomes appear structurally normal. Nondisjunction events are observed when the Mer4 heterozygotes are additionally heterozygous for In(1)FM7.

In Mer4 third instar eye-antennal discs, many cells posterior to the second mitotic wave fail to exit the cell cycle.

In Mer4 pupal eye discs (24hrs after pupariation) exhibit extra interommatidial cells, often forming double rows surrounding the ommatidia. The number of cone cells does not change in the mutants.

Mer4 mutants exhibit overgrown wing imaginal discs.

Mer4 mutants do not exhibit any defect in photoreceptor differentiation.

Mer4 mutant retinae exhibit some extra interommatidial cells.

Homozygous clones in the eye show essentially normal differentiation of ommatidia, with only a few disruptions of ommatidial organisation. The clones are significantly larger than their wild-type sister clones.

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

Mer4 has visible | somatic clone phenotype, enhanceable by kibradel

Suppressed by
NOT suppressed by
Enhancer of
Statement
Reference

Mer4 is an enhancer of visible | somatic clone phenotype of kibradel

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

Mer4 has eye | somatic clone phenotype, enhanceable by kibradel

Mer4 has ommatidium | somatic clone phenotype, enhanceable by kibradel

NOT suppressed by
Statement
Reference
Enhancer of
Statement
Reference

Mer4 is an enhancer of eye phenotype of EBV\BRLF1GMR.PA

Mer4 is an enhancer of eye | somatic clone phenotype of kibradel

Mer4 is an enhancer of ommatidium | somatic clone phenotype of kibradel

NOT Suppressor of
Other
Additional Comments
Genetic Interactions
Statement
Reference

Expression of AckScer\UAS.T:SV5\V5 under the control of Scer\GAL4Ubi.PU in the Mer4 homozygous somatic clones (induced using the eyFLP method) promotes tissue overgrowth in the adult eye.

The proportion of hemisegments with abnormal number of neurons in the asymmetrically dividing RP2 neural lineage is significantly increased in cno2/+;Mer4/+ double heterozygous embryos compared to either of the single heterozygotes or wild type.

Mer4/sav3 double mutant eyes exhibit a massive increase in the number of supernumerary interommatidial cells, compared to either single mutant.

The eye overgrowth phenotype seen in eyes homozygous for Mer4 (generated using the eyFLP method) is not suppressed by expression of kibraScer\UAS.cBa under the control of Scer\GAL4GMR.PF.

Eyes doubly homozygous for Mer4 and kibra3 (generated using the eyFLP method) show stronger overgrowth than eyes singly homozygous for Mer4.

Pupal retinae composed of crb82-04 Mer4 double mutant cells show a massive increase in the number of interommatidial cells.

Mer4 ; kibradel double mutant clones in the eye show a more severe eye overgrowth phenotype and a greater number of interommatidial cells per ommatidium than is seen in either single mutant.

Somatic clones homozygous for Mer4 and exe1 in the antenna or in the dorsal thorax are massively overgrown. In the mid-pupal retina, these clones contain a large excess of inter-ommatidial cells. In the late third instar eye disc, cells in these clones show increased levels of mitosis after (posterior to) the second mitotic wave. Later, at around 25 hours APF, the widespread apotosis seen throughout the developing retina in wild-type and heterozygous cells, is largely suppressed in these clones.

Neither the adult eye phenotype seen in hpoScer\UAS.cUa; Scer\GAL4GMR.PF animals, nor the loss of interommmatidial cells and increased cell death seen in mid-pupal retinas of these animals is suppressed in exBQ Mer4 double homozygous clones.

Mer4; ex697 double mutants exhibit overgrown wing imaginal discs.

Mer4; ex697 double mutant eye-antennal imaginal discs have severely reduced eye primordia with a substantial reduction in or total absence of photoreceptors. In these mutants, photoreceptor development and overall eye field size are severely reduced. The antennal portion is normal or slightly larger than normal and in some cases is duplicated. Apoptosis does not seem to be affected.

Mer4; ex697 somatic clones in contact with the posterior or lateral margin of the eye fail to produce photoreceptors. Those somatic clones located in the middle of the eye field can produce photoreceptors.

Mer4; exe1 somatic clones in contact with the posterior or lateral margin of the eye fail to produce photoreceptors. Those somatic clones located in the middle of the eye field can produce photoreceptors.

Mer4; exe1 double mutant clones exhibit defects in membrane trafficking of proteins such as N and Egfr.

Df(1)N-54l9 Mer4; exe1 triple transheterozygous mutants suppress the Df(1)N-54l9 heterozygous wing notch phenotype.

Clones of cells in the eye, doubly-mutant for ft8 and Mer4 exhibit a dramatic increase in the number of interommatidial cells compared to the more moderate increases seen in single mutants.

exe1;Mer4 double mutants exhibit a large excess of interommatidial cells, in a very similar manner to hpo mutants.

ft422;Mer4 double mutants exhibit a large excess of interommatidial cells, in a very similar manner to hpo mutants.

Both vein and intervein cells can differentiate in Mer4; exe1 double mutant clones in the wing. Clones that intersect the position of the posterior crossvein disrupt its development. Clones in the position of the anterior crossvein develop normally. Within the mutant intervein and vein clones, apparent defects in proliferation control are seen; in the proximal region of the wing, clonal vein tissue forms a raised protrusion. In other regions of the wing, bulges in the veins are also seen, although more frequently vein clones are merely broadened when compared with the surrounding vein. In the intervein regions, the clonal tissue appears to bulge and crinkle within the confines of the normal tissue, suggesting overproliferation. Cells within the intervein clones appear to differentiate as intervein cells, however, the cuticle deposited at the base of each wing hair within the clone appears to be thickened, and is distinct from cuticle produced by either the surrounding heterozygous intervein or vein cells. Mer4; exe1 double mutant clones in the eye appear to disrupt the progression of the morphogenetic furrow, being seen either as small scars with associated clusters of bristles or as elongated scars and associated indentations running from within the eye field towards the anterior margin. These clones do not differentiate ommatidia. The clones are often associated with overproliferated head cuticle.

Xenogenetic Interactions
Statement
Reference

Scer\GAL4T80 expression of Hsap\NF2Scer\UAS.Iso1.T:Zzzz\FLAG partially suppresses lethality (approximately 60% rescue) in Mer4/y male flies; increased genetic dosage (two copies of Hsap\NF2Scer\UAS.Iso1.T:Zzzz\FLAG) further suppresses lethality (72% rescue). Scer\GAL4T80 expression of Hsap\NF2Scer\UAS.Iso2.T:Zzzz\FLAG provides poor rescue of lethality (8%) in Mer4/y male flies; increased genetic dosage completely fails to suppress lethality (0%). Scer\GAL4T80 expression of Hsap\NF2L64P.Scer\UAS.T:Zzzz\FLAG (one or two copies) partially suppresses lethality (approximately 70% rescue) in Mer4/y male flies. Scer\GAL4T80 expression of Hsap\NF2K413E.Scer\UAS.T:Zzzz\FLAG (one copy) partially suppresses lethality (approximately 36% rescue) in Mer4/y male flies; two copies further suppresses lethality (62%). Scer\GAL4T80 expression of Hsap\NF2Δ2-3.Scer\UAS.T:Zzzz\FLAG or Hsap\NF21-301.Scer\UAS.T:Zzzz\FLAG or Hsap\NF2351-595.Scer\UAS.T:Zzzz\FLAG or Hsap\NF21-356.Scer\UAS.T:Zzzz\FLAG or Hsap\NF2300-595.Scer\UAS.T:Zzzz\FLAG (one or two copies) does not suppress lethality (0-2% rescue) in Mer4/y male flies. Scer\GAL4T80 expression of two copies of Hsap\NF2R466X.Scer\UAS.T:Zzzz\FLAG partially suppresses lethality (approximately 11% rescue) in Mer4/y male flies; one copy completely fails to suppress lethality (0%).

Mer4/+ enhances the severity of wing phenotypes seen in female flies with Hsap\NF2Scer\UAS.Iso2.T:Zzzz\FLAG driven by Scer\GAL4ap.PU.

Complementation and Rescue Data
Fails to complement
Comments

Expression of MerT559D.Scer\UAS under the control of Scer\GAL4unspecified can restore the fertility of Mer4 mutants.

Expression of MerScer\UAS.T:Hsap\MYC under the control of Scer\GAL4unspecified can restore the fertility of Mer4 mutants.

Expression of Mer3.Scer\UAS.P\T under the control of Scer\GAL4da.G32 rescues the lethality associated with Mer4.

Images (0)
Mutant
Wild-type
Stocks (1)
Notes on Origin
Discoverer
External Crossreferences and Linkouts ( 0 )
Synonyms and Secondary IDs (4)
References (36)