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Proceedings of the Royal Society B: Biological Sciences logoLink to Proceedings of the Royal Society B: Biological Sciences
. 1998 Apr 22;265(1397):685–692. doi: 10.1098/rspb.1998.0348

Identification of Ca(2+)-activated K+ channel splice variants and their distribution in the turtle cochlea.

E M Jones 1, C Laus 1, R Fettiplace 1
PMCID: PMC1689023  PMID: 9608728

Abstract

Turtle auditory-hair cells are frequency-tuned by the activity of calcium-activated potassium (KCa) channels, a cell's characteristic frequency being determined by the KCa channel density and kinetics which both vary systematically along the cochlea. As a first step towards identifying the source of KCa channel variation, we have isolated, by reverse-transcription polymerase chain reaction on dissociated hair cells, the main cDNAs homologous to the slo gene which encodes the channel's alpha-subunit. A total of six alternatively spliced variants were identified, the smallest of which is 94% identical to a mouse Slo sequence. Variation occurs by insertion of exons at only two splice sites, two of these exons encoding novel 31- and 61-amino acid sequences. As we were unable to detect splicing at other potential sites, we infer that the six variants correspond to naturally occurring combinations. The spatial distribution of the variants, defined by isolating hair cells from different regions of the cochlea, indicated that some isoforms were non-uniformly distributed. Those containing large inserts in the first splice site were notably absent from the highest-frequency region. We suggest that alternative splicing of the slo gene may contribute to variation in KCa channel properties.

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Selected References

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