MULTIPLE MESSENGER-RNA ISOFORMS ENCODING THE MOUSE CARDIAC KV1-5 DELAYED RECTIFIER K+ CHANNEL

作者：ATTALI B; LESAGE F; ZILIANI P; GUILLEMARE E; HONORE E; WALDMANN R; HUGNOT JP; MATTEI MG; LAZDUNSKI M; BARHANIN J

来源：Journal of Biological Chemistry, 1993, 268(32): 24283-24289.

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 (Kv1-5DELTA5'), 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 (Kv1-5DELTA5') arose by an unusual splicing event within the exonic sequence. An additional short cDNA clone (Kv1-5DELTA3') 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 (Kv1-5DELTA5') isoforms elicited similar K+ currents with a drastically decreased efficacy for Kv1-5DELTA5'. The carboxyl-terminal truncated Kv1-5DELTA3' clone was not functional but inhibited the expression of the long isoform.

• 出版日期1993-11-15