Ethanol-modulated camouflage response screen in zebrafish uncovers a novel role for cAMP and extracellular signal-regulated kinase signaling in behavioral sensitivity to ethanol.
Ethanol, a widely abused substance, elicits evolutionarily conserved behavioral responses in a concentration-dependent manner in vivo. The molecular mechanisms underlying such behavioral sensitivity to ethanol are poorly understood. While locomotor-based behavioral genetic screening is successful in identifying genes in invertebrate models, such complex behavior-based screening has proven difficult for recovering genes in vertebrates. Here we report a novel and tractable ethanol response in zebrafish. Using this ethanol-modulated camouflage response as a screening assay, we have identified a zebrafish mutant named fantasma (fan), which displays reduced behavioral sensitivity to ethanol. Positional cloning reveals that fan encodes type 5 adenylyl cyclase (AC5). fan/ac5 is required to maintain the phosphorylation of extracellular signal-regulated kinase (ERK) in the forebrain structures, including the telencephalon and hypothalamus. Partial inhibition of phosphorylation of ERK in wild-type zebrafish mimics the reduction in sensitivity to stimulatory effects of ethanol observed in the fan mutant, whereas, strikingly, strong inhibition of phosphorylation of ERK renders a stimulatory dose of ethanol sedating. Since previous studies in Drosophila and mice show a role of cAMP signaling in suppressing behavioral sensitivity to ethanol, our findings reveal a novel, isoform-specific role of AC signaling in promoting ethanol sensitivity, and suggest that the phosphorylation level of the downstream effector ERK is a critical "gatekeeper" of behavioral sensitivity to ethanol.
Peng
Jisong
J
Department of Biopharmaceutical Sciences, Programs in Human Genetics and Biological Sciences, The Wheeler Center for the Neurobiology of Addiction, University of California, San Francisco, California 94143-2811, USA.
Wagle
Mahendra
M
Mueller
Thomas
T
Mathur
Priya
P
Lockwood
Brent L
BL
Bretaud
Sandrine
S
Guo
Su
S
D000262:Adenylyl Cyclases / Q000235:genetics / Q000378:metabolism; D000324:Adrenocorticotropic Hormone / Q000378:metabolism; D000704:Analysis of Variance; D000818:Animals; D030801:Animals, Genetically Modified; D001522:Behavior, Animal / Q000187:drug effects* / Q000502:physiology; D001921:Brain / Q000033:anatomy & histology / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D002492:Central Nervous System Depressants / Q000494:pharmacology*; D002874:Chromosome Mapping / Q000379:methods; D000242:Cyclic AMP / Q000235:genetics / Q000378:metabolism*; D003624:Darkness; D004305:Dose-Response Relationship, Drug; D051959:ELAV Proteins / Q000378:metabolism; D000431:Ethanol / Q000494:pharmacology*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects / Q000235:genetics; D049452:Green Fluorescent Proteins / Q000235:genetics; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D007814:Larva; D008027:Light; D008124:Locomotion / Q000187:drug effects / Q000235:genetics; D020460:Melanosomes / Q000187:drug effects; D009154:Mutation / Q000235:genetics; D010766:Phosphorylation / Q000187:drug effects; D011930:Reaction Time / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects* / Q000235:genetics; D013037:Spatial Behavior / Q000187:drug effects / Q000502:physiology; D015027:Zebrafish / Q000235:genetics* / Q000502:physiology
D002492:Central Nervous System Depressants; D051959:ELAV Proteins; D007527:Isoenzymes; D049452:Green Fluorescent Proteins; D000431:Ethanol; D000324:Adrenocorticotropic Hormone; D000242:Cyclic AMP; D048049:Extracellular Signal-Regulated MAP Kinases; D000262:Adenylyl Cyclases; C419510:adenylyl cyclase type V