Multiple mRNA isoforms encoding the mouse cardiac Kv1-5 delayed rectifier K+ channel

J Biol Chem. 1993 Nov 15;268(32):24283-9.

Abstract

The mouse Kv1-5 K+ channel cDNA has been cloned from heart. This channel was highly expressed in heart and, to a lesser extent, in other tissues, including brain and thymus. Two alternatively spliced isoforms were found. The longer form encoded a 602-amino acid protein, while in the short form (Kv1-5 delta 5'), the first 200 amino acids lying upstream the transmembrane segment S1 were deleted. RNase protection experiments showed that both Kv1-5 mRNA isoforms are present in the mouse tissues examined, the longer form being predominant. The short mRNA (Kv1-5 delta 5') arose by an unusual splicing event within the exonic sequence. An additional short cDNA clone (Kv1-5 delta 3') that codes for a carboxyl-terminal truncated protein has been isolated. The gene coding sequence contained a single exon and has been mapped on human chromosome 12 (p13) and on mouse chromosome 6 (band F). Expression in Xenopus oocytes revealed that the long (Kv1-5) and the amino-terminal deleted (Kv1-5 delta 5') isoforms elicited similar K+ currents with a drastically decreased efficacy for Kv1-5 delta 5'. The carboxyl-terminal truncated Kv1-5 delta 3' clone was not functional but inhibited the expression of the long isoform.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alternative Splicing
  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Chromosome Mapping
  • DNA, Recombinant
  • Humans
  • Male
  • Mice
  • Molecular Sequence Data
  • Myocardium / metabolism*
  • Oocytes
  • Potassium Channels / genetics*
  • RNA, Messenger / genetics*
  • Xenopus

Substances

  • DNA, Recombinant
  • Potassium Channels
  • RNA, Messenger

Associated data

  • GENBANK/L22218