title: Molecular cloning and characterization of a novel truncated from (ClC-2 beta) of ClC-2 alpha (ClC-2G) in rabbit heart.
abstract: Two cDNAs encoding rabbit heart Cl- channels (rabClC-2 beta and rabClC-2 alpha) were isolated by a PCR cloning strategy. RabClC-2 beta is a novel cDNA consisting of 2998 bp and encoding the 822-amino acid protein, while rabClC-2 alpha is identical to previously reported ClC-2G. RabClC-2 beta is 68 amino acids truncated from NH2-terminus of rabClC-2 alpha, but all 13 putative hydrophobic domains are conserved in rabClC-2 beta. Although rabClC-2 alpha was suggested to be activated by extracellular hypotonicity, expression of rabClC-2 beta in Xenopus oocytes induced large Cl- currents even in the absence of extracellular hypotonicity. Induction of external hypotonicity did not further increase the amplitude of membrane currents. On the other hand, as similar to rabClC-2 alpha, rabClC-2 beta current was augmented by PKA activation. Thus, different RNA processing of the same gene appears to provide two highly homologous PKA-activated Cl- channels with or without responsiveness to cell swelling in rabbit heart.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D000090007:CLC-2 Chloride Channels; D018118:Chloride Channels / Q000096:biosynthesis* / Q000187:drug effects / Q000502:physiology; D003001:Cloning, Molecular / Q000379:methods; D005576:Colforsin / Q000494:pharmacology; D017931:DNA Primers; D018076:DNA, Complementary; D005260:Female; D015723:Gene Library; D006325:Heart Atria; D008564:Membrane Potentials / Q000187:drug effects; D008969:Molecular Sequence Data; D009206:Myocardium / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000096:biosynthesis* / Q000502:physiology; D009865:Oocytes / Q000502:physiology; D009928:Organ Specificity; D018408:Patch-Clamp Techniques; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D011817:Rabbits; D051381:Rats; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014982:Xenopus laevis
chemical_list: D000090007:CLC-2 Chloride Channels; D018118:Chloride Channels; D017931:DNA Primers; D018076:DNA, Complementary; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D011994:Recombinant Proteins; D005576:Colforsin