Progress 06/01/11 to 05/31/16
Outputs
Target Audience:The target audience for Tanouye lab research is basic research scientists, physicians, and other health professionals. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Training and professional development Mark A. Tanouye, Ph.D. (principal investigator) Arunesh Saras, Ph.D. (postdoctoral fellow) Richard Price (graduate student) Undergraduate Research Students: Laura Simon, Harlan Brawer, Patrick Zhang, Na Kang, Veronica Wu, Sae Jin Park, Margarita Federova, Katrina Jiang How have the results been disseminated to communities of interest?Results have been disseminated by publication and research seminars to various communities of interest. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Human seizure disorders are a significant health concern due to the large number of affected individuals, the potentially devastating ramifications of untreated seizure episodes, and the limitations of anti-epileptic drug (AED) options. Studies of human seizure disorders have revealed that susceptibility to seizures is largely influenced by genetic factors. In addition to causing epilepsy, genetic factors can also suppress seizures and epileptogenesis. We propose that the fruit fly Drosophila provides a valuable genetic model for approaching basic biological insights and therapies for human epilepsy. During this project period, we are developing an animal model, in Drosophila, for intractable epilepsy. About 20% of epilepsy patients, nearly 1M Americans, suffer from intractable epilepsy: they continue to experience seizures even with the best available treatment. This poses a difficult neurological problem, as seizures may be the result of injury to the brain or due any one of a number of genetic abnormalities, each of which is likely to respond differently, or worse, not at all, to currently available drugs. Uncontrolled bouts of seizure, especially in infants and children, interfere with normal brain development leading to tragic and permanent deficits in cognitive capabilities. Particularly interesting examples of intractable epilepsy are several idiopathic syndromes associated with mutations in the voltage-gated Na+channel genes, especially the SCN1A gene. Such mutations are associated with three forms of epilepsy in humans: GEFS+ (generalized epilepsy with febrile seizures plus), characterized by febrile seizures that persist beyond the age of 6y; SMEI (severe myoclonic epilepsy in infancy, Dravet's Syndrome), an intractable epilepsy frequently resulting in convulsive status epilepticus; and ICEGTC (intractable childhood epilepsy with generalized tonic-clonic), an atypical SMEI that does not cause myoclonic seizures. We had previously established the Drosophila Na+channel mutantparabss1as a model for human epilepsy. Theparabss1mutation is the most severe ofDrosophilaBS mutations with the lowest threshold for seizure-like activity evoked electrophysiologically, prominent seizure-like behaviors marked by bouts of tonic-clonic-like behavior. The seizure-like phenotypes forparabss1have been found to be nearly completely resistant to suppression by suppressor mutation or drug treatment. During this project period, we showed that the class of mutations affectingDrosophilasynaptic transmitter release may be a good source ofparabss1seizure-suppressors. We identified a suppressor that is capable of amelioratingparabss1phenotypes in hemizygotes and homozygotes. Identification was from a reverse genetics screen generating double mutants of knownDrosophilaneurological mutants in aparabss1genetic background. An especially effectiveparabss1seizure-suppressor is a mutation in the cacophony (cacTS2) gene that encodes the N-type calcium channel responsible for presynaptic neurotransmitter release. In the cacTS2 mutant, seizure-like phenotypes of behavioral hyperexcitability and spontaneous seizure-like neuronal spiking are observed transiently following a shift from permissive temperature to the restrictive temperature of 38o C. These transient seizure-like phenotypes are subsequently replaced by behavioral paralysis and loss of chemical synaptic transmission phenotypes. Thus, the cacTS2 mutant is a temperature-dependent seizure-sensitive mutant. Surprisingly, in double mutant combinations with parabss1, cacTS2, is found to additionally act as a seizure-suppressor mutation. Not only is cacTS2 a seizure-suppressor, it is the most effective suppressor that we have identified. The cacTS2 mutation can suppress phenotypes in parabss1, the most difficult of the seizure-sensitive mutants to suppress thus far identified. We propose that because it interferes with synaptic transmission, cacTS2 causes seizure-suppression by adjusting the functional neurocircuitry responsible for seizure-genesis.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
Saras A, Tanouye MA (2016). Mutations of the Calcium Channel Gene cacophony Suppress Seizures in Drosophila. PLoS Genet 12(1):e1005784. doi: 10.1371/journal.pgen.1005784. eCollection PMID: 26771829
Saras A, Simon LE, Brawer HJ, Price RE, Tanouye MA (2016). Drosophila seizure disorders: genetic suppression of seizure susceptibility. Front Biol 11, 96-108.
Saras A, Tanouye MA (2016). Seizure suppression by high temperature via cAMP modulation in Drosophila. G3 (Bethesda) 13: 3381-3387. PMID: 27558668
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Progress 10/01/14 to 09/30/15
Outputs
Target Audience:The target audience for Tanouye lab research is basic research scientists, physicians, and other health professionals. During this reporting period, one seminar to target a audience was delivered. This was: "Drosophila sodium channels: contributions to seizure-susceptibility" Department of Biology, University of Iowa, April 12, 2015 Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Training and professional development Mark A. Tanouye, Ph.D. (principal investigator) Arunesh Saras, Ph.D. (postdoctoral fellow) Richard Price (graduate student) Jason Kroll (graduate student) Undergraduate Research Students: Karen Wong, Keith Uyemura, Manesh Siddiqi, Laura Simon, Harlan Brawer, Patrick Zhang, Na Kang How have the results been disseminated to communities of interest?Results have been disseminated by publication and research seminars to various communities of interest. What do you plan to do during the next reporting period to accomplish the goals?The mammalian SCN1A Na+channel gene is an important target of human epilepsy mutations, with greater than 600 identified mutations scattered throughout the gene, many of themde novomutations that are effective in one dose, i.e. dominant or haplo-insufficient45,46,47. SCN1A mutations are associated with GEFS+, SMEI and ICEGTC epilepsy disorders. Some mutations are loss-of-function (LoF) alleles, resulting from truncations; others are missense mutations including gain-of-function (GoF) and LoF alleles. For example, the GEFS+ mutation R1648H appears to be a GoF allele from heterologous expression studies, with alteration in Na+channel inactivation. Here, we propose to knock-in selected epilepsy mutations into the endogenousDrosophila paraNa+channel gene. The lesions are all missense mutations responsible for GEFS+, SMEI, or ICEGTC. These will be compared to theparabss1mutant and a control knock-in of theparabss1lesion. 1) For each SCN1A mutation, does it act with a BS paralytic or a TS paralytic phenotype in aDrosophilacontext? For differentDrosophilaparamutations, a BS phenotype indicates a GoF mutation; a TS phenotype indicates a LoF mutation. 2) In theDrosophilacontext, are mutations that cause human GEFS+, phenotypically distinguishable from mutations that cause SMEI or ICEGTC? If so, which mutations most closely resembleparabss1? 3) For each SCN1A mutation in aDrosophilacontext, is it suppressed bygish04895/+which suppressesparabss1/+? Is it suppressed bycacTS2which suppressesparabss1hemizygotes? We use SIRT (site-specific integrase-mediated repeated targeting)mutagenesis of the endogenousDrosophila paragene to generate an allelic series in and around the D-IV, S3-S4 region by repeated targeting. Seizure-susceptibility is evaluated by behavior and electrophysiology in the Na+channel single mutants, and in double mutant combinations withgish04895,cacTS2, and other seizure-suppressor mutations.
Impacts
What was accomplished under these goals?
Human seizure disorders are a significant health concern due to the large number of affected individuals, the potentially devastating ramifications of untreated seizure episodes, and the limitations of anti-epileptic drug (AED) options. Studies of human seizure disorders have revealed that susceptibility to seizures is largely influenced by genetic factors. In addition to causing epilepsy, genetic factors can also suppress seizures and epileptogenesis. We propose that the fruit fly Drosophila provides a valuable genetic model for approaching basic biological insights and therapies for human epilepsy. During this project period, we are developing an animal model, in Drosophila, for intractable epilepsy. About 20% of epilepsy patients, nearly 1M Americans, suffer from intractable epilepsy: they continue to experience seizures even with the best available treatment. This poses a difficult neurological problem, as seizures may be the result of injury to the brain or due any one of a number of genetic abnormalities, each of which is likely to respond differently, or worse, not at all, to currently available drugs. Uncontrolled bouts of seizure, especially in infants and children, interfere with normal brain development leading to tragic and permanent deficits in cognitive capabilities. Particularly interesting examples of intractable epilepsy are several idiopathic syndromes associated with mutations in the voltage-gated Na+channel genes, especially the SCN1A gene. Such mutations are associated with three forms of epilepsy in humans: GEFS+ (generalized epilepsy with febrile seizures plus), characterized by febrile seizures that persist beyond the age of 6y; SMEI (severe myoclonic epilepsy in infancy, Dravet's Syndrome), an intractable epilepsy frequently resulting in convulsive status epilepticus; and ICEGTC (intractable childhood epilepsy with generalized tonic-clonic), an atypical SMEI that does not cause myoclonic seizures. We had previously established the Drosophila Na+channel mutantparabss1as a model for human epilepsy. Theparabss1mutation is the most severe ofDrosophilaBS mutations with the lowest threshold for seizure-like activity evoked electrophysiologically, prominent seizure-like behaviors marked by bouts of tonic-clonic-like behavior. The seizure-like phenotypes forparabss1have been found to be nearly completely resistant to suppression by suppressor mutation or drug treatment. During this project period, we showed that the class of mutations affectingDrosophilasynaptic transmitter release may be a good source ofparabss1seizure-suppressors. We identified a suppressor that is capable of amelioratingparabss1phenotypes in hemizygotes and homozygotes. Identification was from a reverse genetics screen generating double mutants of knownDrosophilaneurological mutants in aparabss1genetic background. An especially effectiveparabss1seizure-suppressor is a mutation in the cacophony (cacTS2) gene that encodes the N-type calcium channel responsible for presynaptic neurotransmitter release. In the cacTS2 mutant, seizure-like phenotypes of behavioral hyperexcitability and spontaneous seizure-like neuronal spiking are observed transiently following a shift from permissive temperature to the restrictive temperature of 38o C. These transient seizure-like phenotypes are subsequently replaced by behavioral paralysis and loss of chemical synaptic transmission phenotypes. Thus, the cacTS2 mutant is a temperature-dependent seizure-sensitive mutant. Surprisingly, in double mutant combinations with parabss1, cacTS2, is found to additionally act as a seizure-suppressor mutation. Not only is cacTS2 a seizure-suppressor, it is the most effective suppressor that we have identified. The cacTS2 mutation can suppress phenotypes in parabss1, the most difficult of the seizure-sensitive mutants to suppress thus far identified. We propose that because it interferes with synaptic transmission, cacTS2 causes seizure-suppression by adjusting the functional neurocircuitry responsible for seizure-genesis.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Kroll JR, Wong KG, Siddiqui FM, Tanouye MA (2015). Disruption of Endocytosis with the Dynamin Mutant shibirets1 Suppresses Seizures in Drosophila. Genetics. 201, 1087-1102. PMID: 26341658
Kroll JR, Saras A, Tanouye MA (2015). Drosophila sodium channel mutations: Contributions to seizure-susceptibility. Exp Neurol 274(Pt A):80-87. PMID: 26093037
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Progress 10/01/13 to 09/30/14
Outputs
Target Audience: The target audience for Tanouye lab research is other research scientists, physicians, and other health professionals. During this reporting period, several seminars to target audiences were delivered. These were: "Drosophila as a model for human epilepsy: suppressing seizures by mutation and by drugs" Neuroboot Camp, Helen Wills Neuroscience Institute, UC Berkeley. "Potassium channels of Mathew" National Centre for Biological Science, Bangalore India Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? Training and professional development Mark A. Tanouye, Ph.D. (principal investigator) Arunesh Saras, Ph.D. (postdoctoral fellow) Iris Howlett (graduate student) Zeid Rusan (graduate student) Richard Price (graduate student) Jason Kroll (graduate student) Undergraduate Research Students: Karen Wong, Keith Uyemura, Manesh Siddiqi How have the results been disseminated to communities of interest? Results have been disseminated by research seminars to various communities of interest. What do you plan to do during the next reporting period to accomplish the goals? The mammalian SCN1A Na+channel gene is an important target of human epilepsy mutations, with greater than 600 identified mutations scattered throughout the gene, many of themde novomutations that are effective in one dose, i.e. dominant or haplo-insufficient45,46,47. SCN1A mutations are associated with GEFS+, SMEI and ICEGTC epilepsy disorders. Some mutations are loss-of-function (LoF) alleles, resulting from truncations; others are missense mutations including gain-of-function (GoF) and LoF alleles. For example, the GEFS+ mutation R1648H appears to be a GoF allele from heterologous expression studies, with alteration in Na+channel inactivation. Here, we propose to knock-in selected epilepsy mutations into the endogenousDrosophila paraNa+channel gene. The lesions are all missense mutations responsible for GEFS+, SMEI, or ICEGTC. These will be compared to theparabss1mutant and a control knock-in of theparabss1lesion. 1) For each SCN1A mutation, does it act with a BS paralytic or a TS paralytic phenotype in aDrosophilacontext? For differentDrosophilaparamutations, a BS phenotype indicates a GoF mutation; a TS phenotype indicates a LoF mutation. 2) In theDrosophilacontext, are mutations that cause human GEFS+, phenotypically distinguishable from mutations that cause SMEI or ICEGTC? If so, which mutations most closely resembleparabss1? 3) For each SCN1A mutation in aDrosophilacontext, is it suppressed bygish04895/+which suppressesparabss1/+? Is it suppressed bycacTS2which suppressesparabss1hemizygotes? We use SIRT (site-specific integrase-mediated repeated targeting)mutagenesis of the endogenousDrosophila paragene to generate an allelic series in and around the D-IV, S3-S4 region by repeated targeting. Seizure-susceptibility is evaluated by behavior and electrophysiology in the Na+channel single mutants, and in double mutant combinations withgish04895,cacTS2, and other seizure-suppressor mutations.
Impacts
What was accomplished under these goals?
Human seizure disorders are a significant health concern due to the large number of affected individuals, the potentially devastating ramifications of untreated seizure episodes, and the limitations of anti-epileptic drug (AED) options. Studies of human seizure disorders have revealed that susceptibility to seizures is largely influenced by genetic factors. In addition to causing epilepsy, genetic factors can also suppress seizures and epileptogenesis. We propose that the fruit fly Drosophila provides a valuable genetic model for approaching basic biological insights and therapies for human epilepsy. During this project period, we are developing an animal model, in Drosophila, for intractable epilepsy. About 20% of epilepsy patients, nearly 1M Americans, suffer from intractable epilepsy: they continue to experience seizures even with the best available treatment. This poses a difficult neurological problem, as seizures may be the result of injury to the brain or due any one of a number of genetic abnormalities, each of which is likely to respond differently, or worse, not at all, to currently available drugs. Uncontrolled bouts of seizure, especially in infants and children, interfere with normal brain development leading to tragic and permanent deficits in cognitive capabilities. Particularly interesting examples of intractable epilepsy are several idiopathic syndromes associated with mutations in the voltage-gated Na+channel genes, especially the SCN1A gene. Such mutations are associated with three forms of epilepsy in humans: GEFS+ (generalized epilepsy with febrile seizures plus), characterized by febrile seizures that persist beyond the age of 6y; SMEI (severe myoclonic epilepsy in infancy, Dravet's Syndrome), an intractable epilepsy frequently resulting in convulsive status epilepticus; and ICEGTC (intractable childhood epilepsy with generalized tonic-clonic), an atypical SMEI that does not cause myoclonic seizures. We had previously established the Drosophila Na+channel mutantparabss1as a model for human epilepsy. Theparabss1mutation is the most severe ofDrosophilaBS mutations with the lowest threshold for seizure-like activity evoked electrophysiologically, prominent seizure-like behaviors marked by bouts of tonic-clonic-like behavior. The seizure-like phenotypes forparabss1have been found to be nearly completely resistant to suppression by suppressor mutation or drug treatment. During this project period, we showed that the class of mutations affectingDrosophilasynaptic transmitter release may be a good source ofparabss1seizure-suppressors. We identified a suppressor that is capable of amelioratingparabss1phenotypes in hemizygotes and homozygotes. Identification was from a reverse genetics screen generating double mutants of knownDrosophilaneurological mutants in aparabss1genetic background. An especially effectiveparabss1seizure-suppressor is a mutation in the shibire gene that encodes dynamin. Temperature sensitive mutations in shibire eventually lead to synaptic depletion of vesicles due to the requirement for Dynamin in the scission event of endocytosis. At room temperature (23oC), eas shits1 flies did not show changes in their seizure-sensitivity compared to the eas control mutant. However, after incubating the flies at an increased temperature for 3 minutes before testing the flies, we observed a large decrease in flies experiencing seizures. The sda mutant has been previously described as a seizure-sensitive mutant easier to suppress mutant than eas. We saw a slight reduction in seizure-sensitivity in the shits1; sda double mutant at room temperature. When we transiently exposed flies to increased temperature for 3 minutes immediately before the seizure-test, we found that double mutant flies with the shi mutation showed strong suppression of seizure-sensitivity phenotype compared to controls. Next, we tested the ability of shits1 to suppress bang-sensitivity in the most severe mutant of the bang-sensitive collection, paralyzedbss1. The paralyzed (para) gene encodes the sole sodium channel in the fly, analogous to the human SCN1A channel. The parabss1 mutation is a semi-dominant gain-of-function mutation that alters channel inactivation, and is a model for intractable epilepsy in Drosophila. Hemizygous parabss1 shits1 male flies were seizure-sensitive at room temperature, but showed reduced seizure-sensitivity levels after being held at 27oC for 3 minutes immediately before testing, indicating a substantial suppression effect even in the most difficult to suppress mutant.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Rusan ZM, Kingsford OA, Tanouye MA (2014). Modeling glial contributions to seizures and epileptogenesis: cation-chloride cotransporters in Drosophila melanogaster. PLoS One. 9(6), e101117. PMID: 24971529.
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Progress 01/01/13 to 09/30/13
Outputs
Target Audience: The target audience for Tanouye lab research is other research scientists, physicians, and other health professionals. During this reporting period, several seminars to target audiences were delivered. These were: “Drosophila as a model for human epilepsy: suppressing seizures by mutation and by drugs”, Neuroboot Camp, Helen Wills Neuroscience Institute, UC Berkeley. “Modeling human epilepsy in Drosophila: suppressing seizures by mutations and by drugs”, UC Berkeley, NSF Research Experiences for Undergraduates evening seminar. “Drosophila as a model for human epilepsy: suppressing seizures by mutation and by drugs”, Williams College, Williamstown, MA. “Epilepsy: modeling neurological dysfunction with Drosophila mutants”, UC Irvine. “Modeling seizure-disorder in Drosophila”, American Epilepsy Society Annual Meeting, Baltimore, MD. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? Mark A. Tanouye, Ph.D. (principal investigator) Arunesh Saras, Ph.D. (postdoctoral fellow) Jascha Pohl, Ph.D. (postdoctoral fellow) Iris Howlett (graduate student) Zeid Rusan (graduate student) Richard Price (graduate student) Jason Kroll (graduate student) Undergraduate Research Students: Stephanie Hu, Vicki Chang, Olivia Kingsford, Peter Chou, Ali Esmaeli, Devon Johnson, Jae Rim, Fariq Siddiqui, Allison Hong, Stephanie Liu, Andrew Lin, Olivia Wung, Meghan Wynne, Hwan Seung How have the results been disseminated to communities of interest? Results have been disseminated by research seminars to various communities of interest. What do you plan to do during the next reporting period to accomplish the goals? The mammalian SCN1A Na+ channel gene is an important target of human epilepsy mutations, with greater than 600 identified mutations scattered throughout the gene, many of them de novo mutations that are effective in one dose, i.e. dominant or haplo-insufficient45,46,47. SCN1A mutations are associated with GEFS+, SMEI and ICEGTC epilepsy disorders. Some mutations are loss-of-function (LoF) alleles, resulting from truncations; others are missense mutations including gain-of-function (GoF) and LoF alleles. For example, the GEFS+ mutation R1648H appears to be a GoF allele from heterologous expression studies, with alteration in Na+ channel inactivation. Here, we propose to knock-in selected epilepsy mutations into the endogenous Drosophila para Na+ channel gene. The lesions are all missense mutations responsible for GEFS+, SMEI, or ICEGTC. These will be compared to the parabss1 mutant and a control knock-in of the parabss1 lesion. 1) For each SCN1A mutation, does it act with a BS paralytic or a TS paralytic phenotype in a Drosophila context? For different Drosophila para mutations, a BS phenotype indicates a GoF mutation; a TS phenotype indicates a LoF mutation. 2) In the Drosophila context, are mutations that cause human GEFS+, phenotypically distinguishable from mutations that cause SMEI or ICEGTC? If so, which mutations most closely resemble parabss1? 3) For each SCN1A mutation in a Drosophila context, is it suppressed by gish04895/+ which suppresses parabss1/+? Is it suppressed by cacTS2 which suppresses parabss1 hemizygotes? We use SIRT (site-specific integrase-mediated repeated targeting)mutagenesis of the endogenous Drosophila para gene to generate an allelic series in and around the D-IV, S3-S4 region by repeated targeting. Seizure-susceptibility is evaluated by behavior and electrophysiology in the Na+ channel single mutants, and in double mutant combinations with gish04895, cacTS2, and other seizure-suppressor mutations.
Impacts
What was accomplished under these goals?
Human seizure disorders are a significant health concern due to the large number of affected individuals, the potentially devastating ramifications of untreated seizure episodes, and the limitations of anti-epileptic drug (AED) options. Studies of human seizure disorders have revealed that susceptibility to seizures is largely influenced by genetic factors. In addition to causing epilepsy, genetic factors can also suppress seizures and epileptogenesis. We propose that the fruit fly Drosophila provides a valuable genetic model for approaching basic biological insights and therapies for human epilepsy. During this project period, we are developing an animal model, in Drosophila, for intractable epilepsy. About 20% of epilepsy patients, nearly 1M Americans, suffer from intractable epilepsy: they continue to experience seizures even with the best available treatment. This poses a difficult neurological problem, as seizures may be the result of injury to the brain or due any one of a number of genetic abnormalities, each of which is likely to respond differently, or worse, not at all, to currently available drugs. Uncontrolled bouts of seizure, especially in infants and children, interfere with normal brain development leading to tragic and permanent deficits in cognitive capabilities. Particularly interesting examples of intractable epilepsy are several idiopathic syndromes associated with mutations in the voltage-gated Na+ channel genes, especially the SCN1A gene. Such mutations are associated with three forms of epilepsy in humans: GEFS+ (generalized epilepsy with febrile seizures plus), characterized by febrile seizures that persist beyond the age of 6y; SMEI (severe myoclonic epilepsy in infancy, Dravet’s Syndrome), an intractable epilepsy frequently resulting in convulsive status epilepticus; and ICEGTC (intractable childhood epilepsy with generalized tonic-clonic), an atypical SMEI that does not cause myoclonic seizures. We had previously established the Drosophila Na+ channel mutant parabss1 as a model for human epilepsy. The parabss1 mutation is the most severe of Drosophila BS mutations with the lowest threshold for seizure-like activity evoked electrophysiologically, prominent seizure-like behaviors marked by bouts of tonic-clonic-like behavior. The seizure-like phenotypes for parabss1 have been found to be nearly completely resistant to suppression by suppressor mutation or drug treatment. During this project period, we showed that the class of mutations affecting Drosophila synaptic transmitter release may be a good source of parabss1 seizure-suppressors. We identified a suppressor which is capable of ameliorating parabss1 phenotypes in hemizygotes and homozygotes. Identification was from a reverse genetics screen generating double mutants of known Drosophila neurological mutants in a parabss1 genetic background. An especially effective parabss1 seizure-suppressor was a mutation in the cacophony (cac) gene that encodes the alpha subunit of the presynaptic Ca++ channel. In double mutant parabss1 cacTS2 hemizygous flies, bang-sensitivity was 34% (a remarkable 66% suppression) at room temperature (240C). For parabss1, suppression by cacTS2 was increased by exposure to high temperature: bang-sensitivity was 13% (87% suppression) following a brief, heat shock (3min at 300C). Heat shock had no effect on the bang-sensitivity of parabss1 single mutant control flies: 100% of the control flies showed BS paralysis. The cacTS2 mutation is a general seizure-suppressor: cacTS2 is also an effective suppressor of sda, and eas.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Kroll JR, Tanouye MA (2013). Rescue of easily shocked mutant seizure sensitivity in Drosophila adults. J Comp Neurol 521, 3500-3507. PMID: 23682034
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Howlett IC, Rusan ZM, Parker L, Tanouye MA (2013). Drosophila as a model for intractable epilepsy: gilgamesh suppresses seizures in para(bss1) heterozygote flies. Genetics G3 (Bethesda) 3,1399-1407. PMI D: 23797108
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Howlett IC, Tanouye MA (2013). Seizure-sensitivity in Drosophila is ameliorated by dorsal vessel injection of the antiepileptic drug valproate. J Neurogenet 27, 143-150. PMID: 23941042
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Progress 01/01/12 to 12/31/12
Outputs
OUTPUTS: Outputs Activities Human seizure disorders are a significant health concern due to the large number of affected individuals, the potentially devastating ramifications of untreated seizure episodes, and the limitations of anti-epileptic drug (AED) options. Studies of human seizure disorders have revealed that susceptibility to seizures is largely influenced by genetic factors. In addition to causing epilepsy, genetic factors can also suppress seizures and epileptogenesis. We propose that the fruit fly Drosophila provides a valuable genetic model for approaching basic biological insights and therapies for human epilepsy. During this project period, we investigated genetic loss-of-function for the kcc gene and its contributions to seizure-sensitivity. kcc mutants are more seizure-susceptible than wild-type flies. kcc is the highly conserved Drosophila ortholog of K+/Cl- cotransporter genes that are expressed in most assayed animal cell types. Here, we examined the spatial and temporal requirements for kcc loss-of-function to modify seizure-susceptibility in flies. Targeted RNAi of kcc in various sets of neurons is sufficient to induce severe seizure-sensitivity. Interestingly, we find that kcc RNAi in glia is particularly effective in causing seizure-sensitivity. kcc knockdown during development is necessary to produce changes in seizure-induction threshold, cell swelling and Blood-Brain Barrier (BBB) degradation in adult flies. Our results suggest that a threshold of K+/Cl- cotransport dysfunction during development and concomitant malformation of the BBB are major determinants of seizure-susceptibility in Drosophila. We are continuing investigation to determine the ionic mechanisms underlying Blood-Brain Barrier degradation. Events. None. Services. None. Products. None. Dissemination. None. PARTICIPANTS: Participants Mark A. Tanouye, Ph.D. (principal investigator) Arunesh Saras, Ph.D. (postdoctoral fellow) Jascha Pohl, Ph.D. (postdoctoral fellow) Iris Howlett (graduate student) Zeid Rusan (graduate student) Richard Price (graduate student) Jason Kroll (graduate student) TARGET AUDIENCES: Target audiences Individuals afflicted with seizure disorders such as epilepsy. PROJECT MODIFICATIONS: Project modifications none
Impacts
Outcomes Impacts The Drosophila mutants that we work on have two dramatic phenotypes. They are seizure-susceptible which may ultimately provide basic information in developing new anti-convulsant drugs for human seizure disorders. They also suffer from paralysis that may provide a basis for designing new types of pesticides to fight insects.
Publications
- No publications reported this period
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