Isolation and characterization of Na+/Ca2+ exchanger gene and splicing isoforms in mice

The Na+/Ca2+ exchanger gene NCX1 is ubiquitously expressed in mammalian tis sues, and encodes several isoforms through alternative RNA splicing. In thi s report, we describe the gene structure that gives rise to the multiple is oforms, and the tissue-specific expression of these isoforms in mice. The m ouse NCX1 gene contains a cluster of six exons (A, B, C, D, E, and Fl which encode a variable region in the large intracellular loop of the protein, a s previously reported in rabbits and humans. Using reverse transcription-po lymerase chain reaction (RT-PCR), expression of the isoforms was examined i n several tissues. We also identified a novel splice variant, which origina te from exons A, C, D, and F. These findings provide new insights into the significance of the large repertoire of NCX1 isoforms.