Sex differences in and hormonal regulation of Kv1 potassium channel gene expression in the electric organ: molecular control of a social signal.
Electric fish communicate with electric organ (EO) discharges (EODs) that are sexually dimorphic, hormone-sensitive, and often individually distinct. The cells of the EO (electrocytes) of the weakly electric fish Sternopygus possess delayed rectifying K+ currents that systematically vary in their activation and deactivation kinetics, and this precise variation in K+ current kinetics helps shape sex and individual differences in the EOD. Because members of the Kv1 subfamily produce delayed rectifier currents, we cloned a number of genes in the Kv1 subfamily from the EO of Sternopygus. Using our sequences and those from genome databases, we found that in teleost fish Kv1.1 and Kv1.2 exist as duplicate pairs (Kv1.1a&b, Kv1.2a&b) whereas Kv1.3 does not. Using real-time quantitative RT-PCR, we found that Kv1.1a and Kv1.2a, but not Kv1.2b, expression in the EO is higher in high EOD frequency females (which have fast EO K+ currents) than in low EOD frequency males (which have slow EO K+ currents). Systemic treatment with dihydrotestosterone decreased Kv1.1a and Kv1.2a, but not Kv1.2b, expression in the EO, whereas treatment with human chorionic gonadotropin (hCG) increased Kv1.2a but not Kv1.1a or Kv1.2b expression in the EO. Thus, systematic variation in the ratios of Kv1 channels expressed in the EO is correlated with individual differences in and sexual dimorphism of a communication signal.
Few
W Preston
WP
Section of Neurobiology and Institute for Neuroscience, University of Texas, Austin, Texas 78712, USA. pfew@u.washington.edu
Zakon
Harold H
HH
D000200:Action Potentials / Q000502:physiology; D000728:Androgens / Q000502:physiology; D000819:Animal Communication; D000818:Animals; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D003001:Cloning, Molecular; D004555:Electric Fish / Q000502:physiology*; D004557:Electric Organ / Q000378:metabolism*; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D006728:Hormones / Q000502:physiology*; D066298:In Vitro Techniques; D008297:Male; D015347:RNA Probes; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012727:Sex Characteristics; D051637:Shaker Superfamily of Potassium Channels / Q000235:genetics*; D012919:Social Behavior
D000728:Androgens; D006063:Chorionic Gonadotropin; D006728:Hormones; D015347:RNA Probes; D012333:RNA, Messenger; D051637:Shaker Superfamily of Potassium Channels