Hair cell-specific splicing of mRNA for the alpha1D subunit of voltage-gated Ca2+ channels in the chicken's cochlea.
The L-type voltage-gated Ca2+ channels that control tonic release of neurotransmitter from hair cells exhibit unusual electrophysiological properties: a low activation threshold, rapid activation and deactivation, and a lack of Ca2+-dependent inactivation. We have inquired whether these characteristics result from cell-specific splicing of the mRNA for the L-type alpha1D subunit that predominates in hair cells of the chicken's cochlea. The alpha1D subunit in hair cells contains three uncommon exons: one encoding a 26-aa insert in the cytoplasmic loop between repeats I and II, an alternative exon for transmembrane segment IIIS2, and a heretofore undescribed exon specifying a 10-aa insert in the cytoplasmic loop between segments IVS2 and IVS3. We propose that the alternative splicing of the alpha1D mRNA contributes to the unusual behavior of the hair cell's voltage-gated Ca2+ channels.
Kollmar
R
R
Howard Hughes Medical Institute and Laboratory of Sensory Neuroscience, The Rockefeller University, New York, NY 10021-6399, USA.
Fak
J
J
Montgomery
L G
LG
Hudspeth
A J
AJ
D017398:Alternative Splicing; D000818:Animals; D015220:Calcium Channels / Q000235:genetics* / Q000378:metabolism; D002645:Chickens; D003051:Cochlea / Q000378:metabolism*; D006198:Hair Cells, Auditory / Q000378:metabolism*; D009928:Organ Specificity; D012333:RNA, Messenger / Q000235:genetics
D015220:Calcium Channels; D012333:RNA, Messenger