Duplication of the Pld gene. The 5' copy retains a functional promoter and its mRNA is expressed. However, it lacks most of exon 9 of the wild type allele, and the encoded protein is C-terminally truncated (owing to a K1002->STOP substitution) and is therefore predicted to be catalytically inactive. The 3' copy lacks a functional promoter and its mRNA is not expressed. Moreover, it lacks exon 1 and most of exon 2 of the wild type allele and contains a premature STOP codon (the E616->STOP substitution) within exon 5. A w+mW.hs marker and a single FRT site are present between the two copies of Pld.
"Pldnull" (Pldnull.5', Pldnull.3') homozygous flies (derived from "Pldnull" heterozygous parents) display an approximately 56% reduction in expected viability in comparison to "Pldnull" heterozygous flies.
"Pldnull" (Pldnull.5', Pldnull.3') homozygous flies (derived from a cross between homozygous "Pldnull" females and heterozygous "Pldnull" males) display an approximately 90% reduction in expected viability.
The reduced viability of "Pldnull" (Pldnull.5', Pldnull.3') homozygous flies progressively decreased after maintaining a homozygous "Pldnull" stock for several generations.
Approximately 50% of "Pldnull" (Pldnull.5', Pldnull.3') embryos exhibit morphological defects prior to or during cellularization.
Approximately 20% of "Pldnull" (Pldnull.5', Pldnull.3') embryos display abnormal gastrulation (as characterized by a thin and shortened germ band), although approximately 20% of these are still able to progress to the larval stage and hatch.
Golgi vesicles are increased in size in "Pldnull" (Pldnull.5', Pldnull.3') embryos compared to controls.
Vesicles (containing Nrt protein) accumulate throughout the subapical and apicolateral cytoplasm in "Pldnull" (Pldnull.5', Pldnull.3') cellularizing embryos.
Approximately 50% of "Pldnull" (Pldnull.5', Pldnull.3') embryos (derived from homozygous "Pldnull" parents) exhibit a substantial delay during cellularization, taking an average of 28% longer to complete the process compared to control embryos. However, approximately 33% of "Pldnull" embryos are wild type in their progression through cellularization, indicating incomplete penetrance of the phenotype.
Pldnull homozygous flies derived from Pldnull heterozygous parents display an approximately 56% reduction in expected viability in comparison to Pldnull heterozygous flies.
Pldnull homozygous flies derived from a cross between homozygous Pldnull females and heterozygous Pldnull males display an approximately 90% reduction in expected viability.
The reduced viability of Pldnull homozygous flies progressively decreased after maintaining a homozygous stock for several generations.
Approximately 50% of Pldnull embryos exhibit morphological defects prior to or during cellularization.
Approximately 20% of Pldnull embryos display abnormal gastrulation (as characterized by a thin and shortened germ band), although approximately 20% of these are still able to progress to the larval stage and hatch.
Golgi vesicles are increased in size in Pldnull embryos compared to controls.
Vesicles (containing Nrt protein) accumulate throughout the subapical and apicolateral cytoplasm in Pldnull cellularizing embryos.
Approximately 50% of Pldnull embryos derived from homozygous Pldnull parents exhibit a substantial delay during cellularization, taking an average of 28% longer to complete the process compared to control embryos. However, approximately 33% of Pldnull embryos derived from homozygous Pldnull parents are wild type in their progression through cellularization, indicating incomplete penetrance of the phenotype.
Pldnull flies exhibit reduced viability during cellularization, but are overtly normal as adults.
Electroretinograms show that Pldnull eyes exhibit approximately 1.9% of the light sensitivity of control eyes. In response to a light pulse (at 570 nm), the mutant retinal photoreceptors show smaller and more variable on- and off-transient membrane potentials, and the intensity responsivity shifts approximately 1.9 log units, compared to controls.
Retinas from Pldnull mutant flies raised for 6 weeks under a 12 hour light/12 hour dark cycle show no apparent changes in morphology.
Retinas from Pldnull mutant flies raised for 1 day under continuous light conditions show no apparent retinal degeneration.
"Pldnull" (Pldnull.5', Pldnull.3') flies exhibit reduced viability during cellularization, but are overtly normal as adults.
Electroretinograms show that "Pldnull" (Pldnull.5', Pldnull.3') eyes exhibit approximately 1.9% of the light sensitivity of control eyes. In response to a light pulse (at 570 nm), "Pldnull" retinal photoreceptors show smaller and more variable on- and off-transient membrane potentials, and the intensity responsivity shifts approximately 1.9 log units, compared to controls.
Retinas from "Pldnull" (Pldnull.5', Pldnull.3') mutant flies raised for 6 weeks under a 12 hour light/12 hour dark cycle show no apparent changes in morphology.
Retinas from "Pldnull" (Pldnull.5', Pldnull.3') mutant flies raised for 1 day under continuous light conditions show no apparent retinal degeneration.
Retinas from Pldnull, norpA7 double mutant flies raised under continuous light conditions show a much more severe retinal degeneration phenotype than the norpA7 single mutants: at 1 day after eclosion, the double mutants already exhibit advanced degeneration (small rhabdomeres and decreased cell body size), while by 6 days after eclosion, retinal degeneration is extensive with only rhabdomeres R7 and R8 remaining.
Retinas from "Pldnull" (Pldnull.5', Pldnull.3'), norpA7 double mutant flies raised under continuous light conditions show a much more severe retinal degeneration phenotype than the norpA7 single mutants: at 1 day after eclosion, the double mutants already exhibit advanced degeneration (small rhabdomeres and decreased cell body size), while by 6 days after eclosion, retinal degeneration is extensive with only rhabdomeres R7 and R8 remaining.
