@article {46607, title = {Lmo4 in the basolateral complex of the amygdala modulates fear learning.}, journal = {PLoS One}, volume = {7}, year = {2012}, month = {2012 Apr 3}, pages = {e34559}, abstract = {

Pavlovian fear conditioning is an associative learning paradigm in which mice learn to associate a neutral conditioned stimulus with an aversive unconditioned stimulus. In this study, we demonstrate a novel role for the transcriptional regulator Lmo4 in fear learning. LMO4 is predominantly expressed in pyramidal projection neurons of the basolateral complex of the amygdala (BLC). Mice heterozygous for a genetrap insertion in the Lmo4 locus (Lmo4gt/+), which express 50\% less Lmo4 than their wild type (WT) counterparts display enhanced freezing to both the context and the cue in which they received the aversive stimulus. Small-hairpin RNA-mediated knockdown of Lmo4 in the BLC, but not the dentate gyrus region of the hippocampus recapitulated this enhanced conditioning phenotype, suggesting an adult- and brain region-specific role for Lmo4 in fear learning. Immunohistochemical analyses revealed an increase in the number of c-Fos positive puncta in the BLC of Lmo4gt/+ mice in comparison to their WT counterparts after fear conditioning. Lastly, we measured anxiety-like behavior in Lmo4gt/+ mice and in mice with BLC-specific downregulation of Lmo4 using the elevated plus maze, open field, and light/dark box tests. Global or BLC-specific knockdown of Lmo4 did not significantly affect anxiety-like behavior. These results suggest a selective role for LMO4 in the BLC in modulating learned but not unlearned fear.

}, keywords = {Adaptor Proteins, Signal Transducing, Amygdala, Animals, Behavior, Animal, Conditioning (Psychology), Cues, Fear, Gene Knockdown Techniques, LIM Domain Proteins, Male, Mice, Mice, Inbred C57BL, Neurons, Protein Transport}, issn = {1932-6203}, doi = {10.1371/journal.pone.0034559}, author = {Maiya, Rajani and Kharazia, Viktor and Lasek, Amy W and Heberlein, Ulrike} } @article {5483, title = {Alk is a transcriptional target of LMO4 and ERα that promotes cocaine sensitization and reward.}, journal = {The Journal of Neuroscience: The Official Journal of the Society for Neuroscience}, volume = {31}, year = {2011}, month = {2011 Oct 5}, pages = {14134-41}, abstract = {

Previously, we showed that the mouse LIM-domain only 4 (Lmo4) gene, which encodes a protein containing two zinc-finger LIM domains that interact with various DNA-binding transcription factors, attenuates behavioral sensitivity to repeated cocaine administration. Here we show that transcription of anaplastic lymphoma kinase (Alk) is repressed by LMO4 in the striatum and that Alk promotes the development of cocaine sensitization and conditioned place preference, a measure of cocaine reward. Since LMO4 is known to interact with estrogen receptor α (ERα) at the promoters of target genes, we investigated whether Alk expression might be controlled by a similar mechanism. We found that LMO4 and ERα are associated with the Alk promoter by chromatin immunoprecipitation and that Alk is an estrogen-responsive gene in the striatum. Moreover, we show that ERα knock-out mice exhibit enhanced cocaine sensitization and conditioned place preference and an increase in Alk expression in the nucleus accumbens. These data define a novel regulatory network involved in behavioral responses to cocaine. Interestingly, sex differences in several behavioral responses to cocaine in humans and rodents have been described, and estrogen is thought to mediate some of these differences. Our data suggest that estrogen regulation of Alk may be one mechanism responsible for sexually dimorphic responses to cocaine.

}, keywords = {Adaptor Proteins, Animals, Cells, Cocaine, Cultured, Estrogen Receptor alpha, Gene Targeting, Genetic, HEK293 Cells, Humans, Inbred C57BL, Knockout, LIM Domain Proteins, Male, Mice, Motor Activity, Newborn, Receptor Protein-Tyrosine Kinases, Reward, Signal Transducing, Transcription}, issn = {1529-2401}, doi = {10.1523/JNEUROSCI.3415-11.2011}, author = {Lasek, Amy W and Gesch, Julie and Giorgetti, Francesco and Kharazia, Viktor and Heberlein, Ulrike} } @article {46610, title = {An evolutionary conserved role for anaplastic lymphoma kinase in behavioral responses to ethanol.}, journal = {PLoS One}, volume = {6}, year = {2011}, month = {2011 Jul 22}, pages = {e22636}, abstract = {

Anaplastic lymphoma kinase (Alk) is a gene expressed in the nervous system that encodes a receptor tyrosine kinase commonly known for its oncogenic function in various human cancers. We have determined that Alk is associated with altered behavioral responses to ethanol in the fruit fly Drosophila melanogaster, in mice, and in humans. Mutant flies containing transposon insertions in dAlk demonstrate increased resistance to the sedating effect of ethanol. Database analyses revealed that Alk expression levels in the brains of recombinant inbred mice are negatively correlated with ethanol-induced ataxia and ethanol consumption. We therefore tested Alk gene knockout mice and found that they sedate longer in response to high doses of ethanol and consume more ethanol than wild-type mice. Finally, sequencing of human ALK led to the discovery of four polymorphisms associated with a low level of response to ethanol, an intermediate phenotype that is predictive of future alcohol use disorders (AUDs). These results suggest that Alk plays an evolutionary conserved role in ethanol-related behaviors. Moreover, ALK may be a novel candidate gene conferring risk for AUDs as well as a potential target for pharmacological intervention.

}, keywords = {Alcohol Drinking, Alcoholics, Animals, Behavior, Animal, Conscious Sedation, Drosophila melanogaster, Drosophila Proteins, Ethanol, Evolution, Molecular, Female, Gene Expression Regulation, Enzymologic, Homeodomain Proteins, Humans, Male, Mice, Polymorphism, Genetic, Receptor Protein-Tyrosine Kinases}, issn = {1932-6203}, doi = {10.1371/journal.pone.0022636}, author = {Lasek, Amy W and Lim, Jana and Kliethermes, Christopher L and Berger, Karen H and Joslyn, Geoff and Brush, Gerry and Xue, Liquan and Robertson, Margaret and Moore, Monica S and Vranizan, Karen and Morris, Stephan W and Schuckit, Marc A and White, Raymond L and Heberlein, Ulrike} } @article {46612, title = {Lmo genes regulate behavioral responses to ethanol in Drosophila melanogaster and the mouse.}, journal = {Alcoholism, Clinical and Experimental Research}, volume = {35}, year = {2011}, month = {2011 Sep}, pages = {1600-6}, abstract = {

BACKGROUND: Previous work from our laboratory demonstrated a role for the Drosophila Lim-only (dLmo) gene in regulating behavioral responses to cocaine. Herein, we examined whether dLmo influences the flies{\textquoteright} sensitivity to ethanol{\textquoteright}s sedating effects. We also investigated whether 1 of the mammalian homologs of dLmo, Lmo3, is involved in behavioral responses to ethanol in mice.

METHODS: To examine dLmo function in ethanol-induced sedation, mutant flies with reduced or increased dLmo expression were tested using the loss of righting (LOR) assay. To determine whether mouse Lmo3 regulates behavioral responses to ethanol, we generated transgenic mice expressing a short-hairpin RNA targeting Lmo3 for RNA interference-mediated knockdown by lentiviral infection of single cell embryos. Adult founder mice, expressing varying amounts of Lmo3 in the brain, were tested using ethanol loss-of-righting-reflex (LORR) and 2-bottle choice ethanol consumption assays.

RESULTS: We found that in flies, reduced dLmo activity increased sensitivity to ethanol-induced sedation, whereas increased expression of dLmo led to increased resistance to ethanol-induced sedation. In mice, reduced levels of Lmo3 were correlated with increased sedation time in the LORR test and decreased ethanol consumption in the 2-bottle choice protocol.

CONCLUSIONS: These data describe a novel and conserved role for Lmo genes in flies and mice in behavioral responses to ethanol. These studies also demonstrate the feasibility of rapidly translating findings from invertebrate systems to mammalian models of alcohol abuse by combining RNA interference in transgenic mice and behavioral testing.

}, keywords = {Adaptor Proteins, Signal Transducing, Animals, Behavior, Animal, Brain, Central Nervous System Depressants, Disease Models, Animal, Drosophila melanogaster, Drosophila Proteins, Ethanol, Female, Genotype, Green Fluorescent Proteins, Homeodomain Proteins, Hypnotics and Sedatives, LIM Domain Proteins, Male, Mice, Mice, Inbred C57BL, Mice, Transgenic, RNA, Small Interfering}, issn = {1530-0277}, doi = {10.1111/j.1530-0277.2011.01506.x}, author = {Lasek, Amy W and Giorgetti, Francesco and Berger, Karen H and Tayor, Stacy and Heberlein, Ulrike} } @article {46623, title = {Drosophila, a genetic model system to study cocaine-related behaviors: a review with focus on LIM-only proteins.}, journal = {Neuropharmacology}, volume = {56 Suppl 1}, year = {2009}, month = {2009}, pages = {97-106}, abstract = {

In the last decade, the fruit fly Drosophila melanogaster, highly accessible to genetic, behavioral and molecular analyses, has been introduced as a novel model organism to help decipher the complex genetic, neurochemical, and neuroanatomical underpinnings of behaviors induced by drugs of abuse. Here we review these data, focusing specifically on cocaine-related behaviors. Several of cocaine{\textquoteright}s most characteristic properties have been recapitulated in Drosophila. First, cocaine induces motor behaviors in flies that are remarkably similar to those observed in mammals. Second, repeated cocaine administration induces behavioral sensitization a form of behavioral plasticity believed to underlie certain aspects of addiction. Third, a key role for dopaminergic systems in mediating cocaine{\textquoteright}s effects has been demonstrated through both pharmacological and genetic methods. Finally, and most importantly, unbiased genetic screens, feasible because of the simplicity and scale with which flies can be manipulated in the laboratory, have identified several novel genes and pathways whose role in cocaine behaviors had not been anticipated. Many of these genes and pathways have been validated in mammalian models of drug addiction. We focus in this review on the role of LIM-only proteins in cocaine-induced behaviors.

}, keywords = {Animals, Animals, Genetically Modified, Behavior, Animal, Cocaine, Cocaine-Related Disorders, Disease Models, Animal, Dopamine Uptake Inhibitors, Drosophila melanogaster, Drosophila Proteins, Homeodomain Proteins, Models, Genetic}, issn = {0028-3908}, doi = {10.1016/j.neuropharm.2008.07.023}, author = {Heberlein, Ulrike and Tsai, Linus T-Y and Kapfhamer, David and Lasek, Amy W} } @article {5487, title = {Distinct behavioral responses to ethanol are regulated by alternate RhoGAP18B isoforms.}, journal = {Cell}, volume = {127}, year = {2006}, month = {2006 Oct 6}, pages = {199-211}, abstract = {

In most organisms, low ethanol doses induce increased activity, while high doses are sedating. To investigate the underlying mechanisms, we isolated Drosophila mutants with altered ethanol responsiveness. Mutations in white rabbit (whir), disrupting RhoGAP18B, are strongly resistant to the sedating effects of ethanol. This resistance can be suppressed by reducing the levels of Rho1 or Rac, implicating these GTPases in the behavioral response to ethanol. Indeed, expression of constitutively active forms of Rho1 or Rac1 in adult flies results in ethanol resistance similar to that observed in whir mutants. The whir locus produces several transcripts, RA-RD, which are predicted to encode three distinct RhoGAPs that share only the GAP domain. The RC transcript mediates the sedating effects of ethanol, while the RA transcript regulates its stimulant effects. Thus, distinct RhoGAPs, encoded by the same gene, regulate different manifestations of acute ethanol intoxication.

}, keywords = {Animal, Animals, Behavior, Brain, Central Nervous System Depressants, Drosophila melanogaster, Drosophila Proteins, Enzyme Activation, Ethanol, Female, GTPase-Activating Proteins, Humans, Molecular Sequence Data, Motor Activity, Mutation, Protein Isoforms, Rabbits, rho GTP-Binding Proteins, Transgenes}, issn = {0092-8674}, doi = {10.1016/j.cell.2006.09.010}, author = {Rothenfluh, Adrian and Threlkeld, Robert J and Bainton, Roland J and Tsai, Linus T-Y and Lasek, Amy W and Heberlein, Ulrike} }