Cloning and functional expression of novel N-type Ca(2+) channel variants.
Voltage-dependent Ca(2+) channels are structurally and functionally diverse. As Ca(2+) currents recorded from embryonic chick dorsal root ganglion (DRG) neurons differ significantly from their mammalian counterparts, information on the primary sequence of the chick channels will help define the structural underpinnings of Ca(2+) channel function. Here, we report the cloning and functional expression of full-length Ca(2+) channel alpha(1B) subunit cDNAs derived from chick DRGs. Two variable regions (A and B) have been identified in the cytoplasmic linker between repeats I and II; a third (C) in the carboxyl terminus extends the open reading frame by 525 nucleotides. The A and C inserts are absent, and the B insert is present in all other class B clones reported to date. The unique shorter channels appear to predominate in DRG neurons. Results represent a requisite first step in defining the structural elements that underlie variations in function and modulation of Ca(2+) channels.
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Department of Physiology, Tufts University School of Medicine, Boston, Massachusetts 02111, USA.
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D000595:Amino Acid Sequence; D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020864:Calcium Channels, N-Type / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D002460:Cell Line; D002642:Chick Embryo; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000378:metabolism; D005727:Ganglia, Spinal / Q000378:metabolism; D015723:Gene Library; D006801:Humans; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D018408:Patch-Clamp Techniques; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution; D014981:Xenopus; D020866:omega-Conotoxin GVIA / Q000494:pharmacology
D002121:Calcium Channel Blockers; D020864:Calcium Channels, N-Type; D018076:DNA, Complementary; D020866:omega-Conotoxin GVIA