|Feature type||allele||Associated gene||Dmel\ltd|
|Map ( GBrowse )|
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|Nature of the Allele|
|Mutations Mapped to the Genome|
comment=Mutation is in the common exon of the predicted ltd transcripts and eliminates the C-terminal 203 amino acid region. Position of mutation on reference sequence inferred by FlyBase curator based on author statement.
|Associated Sequence Data|
|Nature of the lesion|
Amino acid replacement: ??@. Nucleotide substitution: C?G. Mutation is in the common exon of the predicted CG8024 transcripts and eliminates the C-terminal 203 amino acid region.
|Phenotype Manifest In|
eye photoreceptor cell & pigment granule
Mutant flies show a significant decrease in ommochrome pigment levels and some reduction in drosopterin pigment levels compared to wild type.
Mutant flies have reduced red pigment in the eye compared to controls.
The primary pigment cells in ltd1 flies lack the large electron-lucent xanthommatin granules seen in wild type, while the granules in the secondary and tertiary pigment cells are fewer in number than normal and abnormal in shape and density of their content. The photoreceptor cells lack the small xanthommatin pigment granules seen in wild type.
Uptake of kynurenine, which is produced in the fat body, by the Malpighian tubes, where it is converted to 3-hydrokynurenine, is defective; similar defect seen in eye discs. Sullivan and Sullivan postulate that ltd is a transport mutant that prevents the substrate kynurenine from reaching the sites of its conversion to ommochrome.
Exhibits reduced levels of phenoazinone synthetase, an enzyme involved in the condensation of 3OH kynurenine molecules to xanthommatin, as do other mutants deficient in ommochrome synthesis.
Administration of 3 hydroxykynurenine without effect on eye colour.
Studied phenotypic interaction with other eye-color mutants.
Deficient in ommochrome synthesis. Lack detectable levels of 3OH kynurenine despite normal levels of kynurenine hydroxylase activity.
Eye colour: clear, light, translucent yellowish pink; resembles lt1 but is lighter, darkens with age. Ocellus colour: colourless. Malpighian tubule colour: colourless.
ltd1 has eye color defective phenotype, enhanceable by auxScer\UAS.cHa/Scer\GAL4GMR.PF/Scer\GAL4GMR.PF
|Phenotype Manifest In|
|NOT suppressed by|
The reduction in ommochrome pigment levels that is seen in ltd flies is not affected by HPS4[W515X].
The reduction in red pigment in the eye seen in ltd blos1[ex2] double mutants is more severe than that seen in either single mutant.
Expression of aux[Scer\UAS.cHa] under the control of Scer\GAL4[GMR.PF] enhances the loss of red eye pigment that is seen in ltd flies.
Eye colour: ltd1; psnb eyes are lighter and have significantly reduced levels of red pigment compared to either single mutant.
The level of pteridine eye pigments in ltd1 ; ca1 double mutant flies resembles that seen in ca1 single mutants. The level of pteridine eye pigments in g1 ; ltd1 or rb1 ; ltd1 double mutant flies are significantly lower than that of the corresponding single mutants.
|Complementation & Rescue Data|
|Stocks ( 5 )|
|Notes on Origin|
|External Crossreferences & Linkouts|
|Synonyms & Secondary IDs ( 3 )|
|Secondary FlyBase IDs|
|References ( 15 )|