|Feature type||allele||Associated gene||Dmel\trpl|
|Also Known As||trplp302|
|Map ( GBrowse )|
|Allele class||amorphic allele - genetic evidence, loss of function allele|
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|Nature of the Allele|
|Mutations Mapped to the Genome|
|Associated Sequence Data|
|Nature of the lesion|
Amino acid replacement: ?302@. Amber nonsense codon leading to premature termination of the polypeptide chain before the first transmembrane segment.
|Phenotype Manifest In|
photoreceptor cell & axon
Compound action potentials can be evoked by sound in the antennal nerve of mutant flies, but the sound particle velocities required to elicit the response is increased compared to wild type. Nonlinear mechanical amplification is significantly reduced compared to wild type.
Mutant flies exhibit the wild type avoidance of aristolochic acid in food choice assays.
The normal preference of third instar larvae for 17.5[o]C over 14[o]C in a two-way choice test is eliminated in trpl and trpl/trpl[MB03075] larvae.
capa stimulated fluid transport rates are significantly reduced in Malpighian tubules from trpl302 animals compared to control tubules, while the basal rate of secretion is unaffected.
Mutant flies show an electroretinogram response that is similar to wild-type in response to a 10 second pulse of light.
The reduction in electroretinogram (ERG) amplitude seen in flies exposed to constant light is not suppressed by trpl302.
Wild-type flies kept in the dark are significantly more sensitive to background light than wild-type flies kept in the light or trpl302 flies kept in light or darkness.
Mutant phenotype can be detected using ERG and intracellular recording techniques after prolonged stimuli. The receptor potential has a smaller sustained component than wild type, with altered time course of decay, though peak responses are similar. The response is accompanied by oscillations during stimulus and hyperpolarization after stimulus termination. Mutants also show inability to adapt to dim background illuminations. Refractory period and response latency are wild type.
When IBMX is applied to trpl302 mutant flies the macroscopic response is slowed in a way that is no different to that of wild type flies exposed to IBMX.
Erev in mutant photoreceptors shows a small but statistically highly significant positive shift compared to wild type. Light sensitive conductance is even more permeable to Na+ than wild type. Permeability to Li+ is roughly the same in wild type, trpl302 and trp2 mutants. In general the permeability of mutant photoreceptors to Ca2+, Na+, Li+, Ba2+, Mg2+ and Mn2+ is higher than that for wild type. The I-V relationship of the light sensitive conductance is similar to that of wild type in always showing a pronounced dual rectification. Shows no biphasic reversal potential behaviour with lowered external calcium. Estimated single channel conductance is 4pS. La3+ completely blocks the light response. Light sensitive conductance is facilitated by Ca2+.
|Phenotype Manifest In|
|NOT Suppressor of|
The trpl; trp double mutant has no functional trp and trpl channels and shows no response to light.
Dissociated Xport, trpl double mutant ommatidia show a residual response to brief light flashes; sensitivity is reduced ~500-fold with respect to wild type and 25-fold with respect to Xport.
Illumination of dissociated, patch-clamped ommatidia from trp;trpl double mutants show activation of the whole phototransduction cascade, do not show any light-induced current or Ca[2+] influx, but do show a normal light-dependent modulation of the delayed rectifier current mediated by Shab channels. Increasing the light level by a factor of ten results in an upregulation of approximately 30% and recovery to baseline within 30 minutes, similar to wildtype controls.
trp9; trpl302 individual photoreceptors form the correct number of synapses per presynaptic terminal independently of cartridge composition. The photoreceptor terminals of these mutants show an increase in glial invaginations.
capa stimulated fluid transport rates are significantly reduced in Malpighian tubules from trpl302 trp9 animals compared to control tubules, while the basal rate of secretion is unaffected.
trpl302 ; trp14 flies show a electroretinogram response in response to a 10 second pulse of light that is similar to that seen in trp14 single mutants. trpl302 ; trpL612F.ninaE trp9 flies have a wild-type electroretinogram response. trpl302 ; trpninaE.PW trp9 flies have a wild-type electroretinogram response. trpl302 ; trpR671Q.ninaE trp9 flies have a transient electroretinogram response to a 10 second pulse of light.
trp9 ; trpl302 double mutants show a reduced depolarisation response to anoxia in the photoreceptors compared to wild-type flies; the amplitude of anoxia-induced depolarisation in the double mutants is half that of wild type and the response kinetics are much slower than normal.
In trp9,trpl302 double mutants the second, large phase depolarization response to anoxia (caused by N2 and measured in the eye by extracellular voltage change recordings), fails, indicating that the small but not the large phase of the response resulted from accumulation of K+ in the extracellular space. In trp9, trpl302 double mutants the Ca2+ response to anoxia is virtually abolished.
Excised patches from rhabdomeral membranes show no sustained spontaneous activity nor high frequency burst-like behavior in trp9,trpl302 double mutants.
Rhabdomeres of trpl302,inaD1 double mutants are intact in 1 day old flies. ERG light responses of trpl302,inaD1 and trpl302,trp2 are small and transient, but the response amplitude of trpl302,inaD1 is significantly smaller than that of trpl302,trp2. Similarly, refractory period and response latency defects are more severe for trpl302,inaD1 than for trpl302,trp2.
In trp1, trpl302 double mutants light sensitive channels are not activated by the application of linolenic acid, whereas they are activated in single mutant channels.
Double mutant analysis comparing the receptor potentials of trpl302 with inaFP106x; trpl302 or trp2; trpl302 or trp9; trpl302 showed that the effects of inaFP106x are as severe as those of trp2 and are specific to the trp channel.
Behavioural rhythms of trp9 trpl302 double mutants show reduced resetting in response to a pulse of light.
trpl302; trp2 double mutants are almost blind as judged by response to saturating ultraviolet flashes and ERG recordings. trpl302; trp1 double mutants are blind.
Whole-cell patch-clamp recordings of photoreceptors display sensitivity and response kinetics indistinguishable from wild type. trpl302; trp2 mutants display a dramatic loss of responsiveness, the residual current is due to a small amount of functional trp channel. trpl302; trp2 mutants exhibit a dramatic bump phenotype.
The presence of trp::trpl[ninaE.trp1-675.trpl681-1124.T:Avic\GFP-EGFP] in trpl; trp double mutants results in a response to light that declines towards baseline during prolonged intense light. The presence of trp::trpl[ninaE.trpl1-336.T:Avic\GFP-EGFP] in trpl; trp double mutants results in a response to light that declines towards baseline during prolonged intense light. The presence of trp::trpl[ninaE.trpl1-336.trp328-675.trpl681-1124.T:Avic\GFP-EGFP] in trpl; trp double mutants results in a response to light that declines towards baseline during prolonged intense light. The presence of trp::trpl[ninaE.trp1-328.trpl336-681.trp675-1275.T:Avic\GFP-EGFP] in trpl; trp double mutants results in a response to light that declines towards baseline during prolonged intense light.
|Complementation & Rescue Data|
|Stocks ( 1 )|
|Notes on Origin|
|External Crossreferences & Linkouts|
|Synonyms & Secondary IDs ( 3 )|
(Hiesinger et al., 2006, Satoh et al., 2010, Huang et al., 2004, Wang et al., 2005, Meyer et al., 2006, Vasiliauskas et al., 2011, Rosenbaum et al., 2006, Krause et al., 2008, Chen et al., 2010, Kwon et al., 2010, Kim et al., 2010, Rosenbaum et al., 2011, Elsaesser et al., 2010, Senthilan et al., 2012, Richter et al., 2011)
|Secondary FlyBase IDs|
|References ( 33 )|
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|Recent research papers ( 4 )|