General Information
Symbol
Dmel\crb8F105
Species
D. melanogaster
Name
FlyBase ID
FBal0001816
Feature type
allele
Associated gene
Associated Insertion(s)
Carried in Construct
Also Known As
crb1, crumbs8F105
Nature of the Allele
Mutations Mapped to the Genome
 
Type
Location
Additional Notes
References
point mutation
Nucleotide change:
C24313808T
Reported nucleotide change:
C6581T
Amino acid change:
Q2124term | crb-PA; Q2167term | crb-PB; Q2231term | crb-PC; Q2181term | crb-PD
Reported amino acid change:
Q2125term
Associated Sequence Data
DNA sequence
Protein sequence
 
 
Progenitor genotype
Cytology
Polytene chromosomes normal.
Nature of the lesion
Statement
Reference
Nucleotide substitution: C6581T.
The premature stop codon is predicted to result in a truncated protein lacking the last 23 amino acids of the wild-type protein.
Amino acid replacement: Q2125term.
Expression Data
Reporter Expression
Additional Information
Statement
Reference
In the crb8F105 mutant, crb protein is observed on the basal and lateral cell membranes in addition to the apical membranes.
 
Marker for
Reflects expression of
Reporter construct used in assay
Human Disease Model Data
Disease Ontology
Models ( 0 )
Disease
Evidence
References
Interactions ( 0 )
Disease
Interaction
References
Comments ( 0 )
 
Phenotypic Data
Phenotypic Class
Phenotype Manifest In
Detailed Description
Statement
Reference
crb8F105 homozygotes die as embryos with only pieces of cuticle formed.
crb8F105 mutant two hour-old embryos show chromosome defects such as chromosome-free centrosomes, chromosomal bridges and abnormal microtubule pattern during mitosis.
In crb8F105 mutant ocelli, rhabdomeres are in the correct location in the retina and exhibit normal shapes, but irregular alignment, and adherens junctions do not form correctly in photoreceptor cells. Ocellar photoreceptor cells in crb8F105 mutants do not show signs of degeneration after light exposure.
Homozygous follicle cell clones show multilayering of cells in 42% of cases and show a flattened cells compared to wild-type cells in 22% of cases.
crb1 mutant embryos at stage 15 show renal tubules that fail to elongate, presenting the appearance of disorganised clusters. Ultrastructural analysis reveals that the zona adherens have dispersed by this stage.
Homozygous clones that cover large areas of the wing can be recovered, indicating that loss of crb function does not compromise cell viability.
When flies with eyes containing homozygous clones are kept in constant light conditions for 7 days, no retinal degeneration is seen.
Epithelial cells of ectodermal origin lose their apicobasal polarity resulting in the loss of epithelial integrity and cell death. Both epidermal and amnioserosa cells of stage 10 lack zonula adherens junctions (ZA) and the number of spot adherens junctions (SAJ) is lower. The structure of all ectodermally derived epithelia is affected to varying extents.
Epithelial tissues begin to degenerate from stage 11 onward in homozygous embryos. The epidermis, atrium and pharynx degenerate rapidly and almost completely, while the oesophagus, proventriculus and parts of the hindgut degenerate more slowly and to a lesser extent. Salivary glands and Malpighian tubules are reduced in size and are often dislocated.
Strong crb phenotype. Embryos almost completely lack cuticle due to cell death in epidermal primordium. P{lacZ}6-81 enhancer detection line specifically expresses Ecol\lacZ in the tracheal system, and reveals that morphogenetic abnormalities in the developing tracheal system result in a only a few aggregates of tracheal cells. Morphogenetic abnormalities and cell death were detected in the presumptive foregut and hindgut by fkh protein staining. Salivary glands also undergo cell death.
Severe disruption in the organization of ectodermally derived epithelia, possibly cell death in the tissues.
embryonic lethal many small holes in cuticle.
External Data
Interactions
Show genetic interaction network for Enhancers & Suppressors
Phenotypic Class
Suppressed by
Enhancer of
Statement
Reference
Suppressor of
Statement
Reference
Phenotype Manifest In
Suppressed by
Enhancer of
NOT Enhancer of
Statement
Reference
crb8F105 is a non-enhancer of epidermal cell phenotype of ctC145
Suppressor of
Statement
Reference
NOT Suppressor of
Statement
Reference
crb8F105 is a non-suppressor of epidermal cell phenotype of ctC145
Other
Additional Comments
Genetic Interactions
Statement
Reference
The embryonic cuticular defects and lethality observed in crb8F105 homozygotes are weakly suppressed by combination with single copy of chem1 and more strongly so by combination with two copies, some crb8F105 mutant embryos heterozygous or homozygous for chem1 reach adulthood when cultured separately without larvae of other genotypes. Conversely, crb8F105 heterozygosity partially suppresses chem1 mutant embryonic cuticular defects and lethality and the surviving larvae (cultured separately) reach the adult stage at the same rate as sibling double heterozygotes. The cuticular phenotype of crb8F105;chem1 homozygous double mutants is improved relative to crb8F105 single mutants but worsened relative to chem1 single homozygotes.
The epidermis of crb1 Kr1 double mutant embryos exhibit relatively normal distributions of cell polarity and junctional proteins. There is some suppression of the crb1 phenotype; a continuous, through reduced, cuticle sheet is formed. Tubules in ctC145; crb1 double-mutant embryos resemble those of ctC145 single mutants; they form epithelial blisters.
Xenogenetic Interactions
Statement
Reference
Complementation and Rescue Data
Partially rescued by
crb8F105 is partially rescued by crbintra.GMR
Comments
Images (0)
Mutant
Wild-type
Stocks (1)
Notes on Origin
Discoverer
Comments
Comments
A strong allele of crb.
Strong crb allele.
External Crossreferences and Linkouts ( 0 )
Synonyms and Secondary IDs (4)
References (26)