Mutant analysis of the Shal (Kv4) voltage-gated fast transient K+ channel in Caenorhabditis elegans.
Shal (Kv4) alpha-subunits are the most conserved among the family of voltage-gated potassium channels. Previous work has shown that the Shal potassium channel subfamily underlies the predominant fast transient outward current in Drosophila neurons (Tsunoda, S., and Salkoff, L. (1995) J. Neurosci. 15, 1741-1754) and the fast transient outward current in mouse heart muscle (Guo, W., Jung, W. E., Marionneau, C., Aimond, F., Xu, H., Yamada, K. A., Schwarz, T. L., Demolombe, S., and Nerbonne, J. M. (2005) Circ. Res. 97, 1342-1350). We show that Shal channels also play a role as the predominant transient outward current in Caenorhabditis elegans muscle. Green fluorescent protein promoter experiments also revealed SHL-1 expression in a subset of neurons as well as in C. elegans body wall muscle and in male-specific diagonal muscles. The shl-1 (ok1168) null mutant removed all fast transient outward current from muscle cells. SHL-1 currents strongly resembled Shal currents in other species except that they were active in a more depolarized voltage range. We also determined that the remaining delayed-rectifier current in cultured myocytes was carried by the Shaker ortholog SHK-1. In shl-1 (ok1168) mutants there was a significant compensatory increase in the SHK-1 current. Male shl-1 (ok1168) animals exhibited reduced mating efficiency resulting from an apparent difficulty in locating the hermaphrodite vulva. SHL-1 channels are apparently important in fine-tuning complex behaviors, such as mating, that play a crucial role in the survival and propagation of the species.
Fawcett
Gloria L
GL
Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Santi
Celia M
CM
Butler
Alice
A
Harris
Thanawath
T
Covarrubias
Manuel
M
Salkoff
Lawrence
L
D000818:Animals; D017173:Caenorhabditis elegans; D004252:DNA Mutational Analysis; D004594:Electrophysiology; D005799:Genes, Dominant; D049452:Green Fluorescent Proteins / Q000378:metabolism; D009474:Neurons / Q000378:metabolism; D009865:Oocytes / Q000378:metabolism; D010641:Phenotype; D011401:Promoter Regions, Genetic; D034622:RNA Interference; D018075:RNA, Complementary / Q000378:metabolism; D051672:Shal Potassium Channels / Q000235:genetics* / Q000502:physiology*; D014981:Xenopus / Q000378:metabolism
D018075:RNA, Complementary; D051672:Shal Potassium Channels; D049452:Green Fluorescent Proteins