Complementation of physiological and behavioral defects by a slowpoke Ca(2+) -activated K(+) channel transgene.
The Drosophila slowpoke gene encodes a large conductance calcium-activated potassium channel used in neurons, muscle, and some epithelial cells. Tissue-specific transcriptional promoters and alternative mRNA splicing generate a large array of transcripts. These distinct transcripts are thought to tailor the properties of the channel to the requirements of the cell. Presumably, a single splice variant cannot satisfy the specific needs of all cell types. To test this, we examined whether a single slowpoke splice variant was capable of complementing all slowpoke behavioral phenotypes. Null mutations in slowpoke cause animals to be semiflightless and to manifest an inducible "sticky-feet" phenotype. The well-characterized slowpoke transcriptional control region was used to direct the expression of a single slowpoke splice variant (cDNA H13) in transgenic flies. The endogenous gene in these flies had been inactivated by the slo(4) mutation. Action-potential recordings and voltage-clamp recordings demonstrated the production of functional channels from the transgene. The transgene completely complemented the flight defect, but not the sticky-feet phenotype. We conclude that distinct slowpoke channel isoforms, produced by alternative splicing, are not interchangeable and are required for proper function of different cell types.
Section of Neurobiology and the Institute for Cellular and Molecular Biology, The University of Texas at Austin, 78712-1064, USA.
R
R
Brenner
J Y
JY
Yu
K
K
Srinivasan
L
L
Brewer
J L
JL
Larimer
J L
JL
Wilbur
N S
NS
Atkinson
D000200:Action Potentials / Q000502:physiology; D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D004330:Drosophila / Q000235:genetics / Q000502:physiology*; D029721:Drosophila Proteins; D005091:Exons; D005426:Flight, Animal; D005816:Genetic Complementation Test; D014644:Genetic Variation; D051036:Large-Conductance Calcium-Activated Potassium Channels; D008958:Models, Molecular; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000502:physiology; D015221:Potassium Channels / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D024681:Potassium Channels, Calcium-Activated; D011401:Promoter Regions, Genetic; D017433:Protein Structure, Secondary; D014158:Transcription, Genetic
D029721:Drosophila Proteins; D051036:Large-Conductance Calcium-Activated Potassium Channels; D015221:Potassium Channels; D024681:Potassium Channels, Calcium-Activated; C494844:slo protein, Drosophila