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.
Brenner
R
R
Section of Neurobiology and the Institute for Cellular and Molecular Biology, The University of Texas at Austin, 78712-1064, USA.
Yu
J Y
JY
Srinivasan
K
K
Brewer
L
L
Larimer
J L
JL
Wilbur
J L
JL
Atkinson
N S
NS
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