Identification of alternatively spliced Na(+)-Ca2+ exchanger isoforms expressed in the heart.

Abstract

Alternatively spliced isoforms of Na+-Ca2+ exchanger were found from various tissues and species. RT-PCR amplification was performed on the basis of our cloned mouse cardiac Na+-Ca2+ exchanger and four alternatively spliced isoforms of Na+-Ca2+ exchanger were identified. Three (NCX1.3, NCX1.4, and NCX1.12) of them were first identified in the heart, and one isoform (NCX1.12) was a novel spliced variant. These four spliced variants were present in the embryonic and adult: atria and ventricles. Different cell types of the heart expressed different spliced isoforms of Na+-Ca2+ exchanger. Southern blot analysis indicated that the Na+-Ca2+ exchanger gene existed as a single copy in the mouse genome. Thus, the Na+-Ca2+ exchanger isoforms expressed in mouse heart are consistent with being produced by alternative splicing and they may have different functions in various cell types in the mouse heart. (C) 1998 Elsevier Science Inc.