| First Author | Lee-Kirsch MA | Year | 1999 |
| Journal | Circ Res | Volume | 84 |
| Issue | 2 | Pages | 240-6 |
| PubMed ID | 9933256 | Mgi Jnum | J:281231 |
| Mgi Id | MGI:6378214 | Doi | 10.1161/01.res.84.2.240 |
| Citation | Lee-Kirsch MA, et al. (1999) Distinct renin isoforms generated by tissue-specific transcription initiation and alternative splicing. Circ Res 84(2):240-6 |
| abstractText | The aspartyl protease renin catalyzes the initial and rate-limiting step in the formation of the biologically active peptide angiotensin II. It is mainly synthesized in the kidney as a preprohormone and secreted via constitutive and regulated pathways. We identified a novel transcript of the rat renin gene, renin b, characterized by the presence of an alternative first exon (exon 1b) that is spliced to exon 2 of the known transcript, termed renin a. We demonstrated that renin b is exclusively expressed in the brain. In contrast, renin a was not expressed in the brain. Using primer extension assays, we mapped the transcriptional start site of this novel mRNA within intron 1 of the rat genomic sequence, suggesting the presence of a brain-specific promoter within intron 1. The presence of a brain-specific renin isoform is evolutionally conserved, as demonstrated by the finding of renin b isoforms in mice and humans. The predicted protein renin b lacks the prefragment as well as a significant portion of the profragment and is therefore predicted not to be a secreted protein, unlike the classically described isoform renin a. As shown by in vitro translation of full-length renin b mRNA in the presence of microsomal membranes, renin b was not targeted into the endoplasmatic reticulum and remained intracellularly in transiently transfected AtT-20 cells. These findings provide evidence for a novel pathway of intracellular angiotensin generation that occurs exclusively in the brain. |
