Distribution of Ca2+-activated K+ channel isoforms along the tonotopic gradient of the chicken's cochlea.
In some cochleae, the number and kinetic properties of Ca2+-activated K+ (KCa) channels partly determine the characteristic frequency of each hair cell and thus help establish a tonotopic map. In the chicken's basilar papilla, we found numerous isoforms of KCa channels generated by alternative mRNA splicing at seven sites in a single gene, cSlo. In situ polymerase chain reactions demonstrated cSlo expression in hair cells and revealed differential distributions of KCa channel isoforms along the basilar papilla. Analysis of single hair cells by the reverse transcription polymerase chain reaction confirmed the differential expression of channel variants. Heterologously expressed cSlo variants differed in their sensitivities to Ca2+ and voltage, suggesting that the distinct spatial distributions of cSlo variants help determine the tonotopic map.
Rosenblatt
K P
KP
Howard Hughes Medical Institute and Laboratory of Sensory Neuroscience, The Rockefeller University, New York, New York 10021-6399, USA.
Sun
Z P
ZP
Heller
S
S
Hudspeth
A J
AJ
D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000378:metabolism; D002642:Chick Embryo; D002645:Chickens / Q000378:metabolism*; D003051:Cochlea / Q000378:metabolism* / Q000502:physiology; D018076:DNA, Complementary / Q000235:genetics; D006309:Hearing / Q000502:physiology*; D007536:Isomerism; D051036:Large-Conductance Calcium-Activated Potassium Channels; D008969:Molecular Sequence Data; D015221:Potassium Channels / Q000235:genetics / Q000378:metabolism*; D024681:Potassium Channels, Calcium-Activated; D012326:RNA Splicing; D012333:RNA, Messenger / Q000378:metabolism; D014018:Tissue Distribution
D018076:DNA, Complementary; D051036:Large-Conductance Calcium-Activated Potassium Channels; D015221:Potassium Channels; D024681:Potassium Channels, Calcium-Activated; D012333:RNA, Messenger