| First Author | Li XF | Year | 1999 |
| Journal | J Biol Chem | Volume | 274 |
| Issue | 12 | Pages | 8153-60 |
| PubMed ID | 10075718 | Mgi Jnum | J:54277 |
| Mgi Id | MGI:1334878 | Doi | 10.1074/jbc.274.12.8153 |
| Citation | Li XF, et al. (1999) A circularized sodium-calcium exchanger exon 2 transcript. J Biol Chem 274(12):8153-60 |
| abstractText | Previous reports of Na/Ca exchanger gene 1 (NCX1) expression have revealed a major RNA transcript of 7 kilobase pairs (kb), minor transcripts of approximately 13 and approximately 4 kb, and a relatively abundant 1.8-kb RNA band. In the present report we demonstrate that the 1.8-kb message, which has a tissue and subcellular distribution matching that of full-length NCX1 but is not polyadenylated, corresponds to a perfectly circularized exon 2 species. The circular transcript contained the normal NCX1 start codon, a new stop codon introduced as a consequence of circularization, and encoded a protein corresponding to the NH2-terminal portion of NCX1, terminating just after amino acid 600 in the cytoplasmic loop. A linear version of the circular transcript was prepared and transfected into HEK-293 cells. A protein, matching the predicted size of approximately 70 kDa, was expressed, and the transfected cells possessed Na/Ca exchange activity. Although in native tissue we could not detect a protein corresponding exactly to that predicted from the circular transcript, a prominent band of slightly shorter size, possibly representing further proteolytic processing of circular transcript protein, was observed in membranes from LLC-MK2 cells and rat kidney. |
