gms | German Medical Science

29. Wissenschaftlicher Kongress der Deutschen Hochdruckliga

Deutsche Hochdruckliga e. V. DHL ® - Deutsche Hypertonie Gesellschaft Deutsches Kompetenzzentrum Bluthochdruck

23. bis 25.11.2005, Berlin

A splicing enhancer in exon 2 is essential for functional expression of angiotensinogen

Ein Splicing Enhancer in Exon 2 ist essentiell für die funktionelle Expression des Angiotensinogen-Gens

Meeting Abstract

  • M. Bader - Max-Delbrück-Zentrum, Berlin-Buch (Berlin, D)
  • C. Cardoso - Max-Delbrück-Zentrum, Berlin-Buch (Berlin, D)
  • C. Wilhelm - Max-Delbrück-Zentrum, Berlin-Buch (Berlin, D)
  • C. Cayla - Max-Delbrück-Zentrum, Berlin-Buch (Berlin, D)
  • D. Cabrini - Universidade de Santa Catarina, Curitiba
  • T. Walther - Erasmus Medical School, Rotterdam

Hypertonie 2005. 29. Wissenschaftlicher Kongress der Deutschen Hochdruckliga. Berlin, 23.-25.11.2005. Düsseldorf, Köln: German Medical Science; 2006. Doc05hochP163

Die elektronische Version dieses Artikels ist vollständig und ist verfügbar unter: http://www.egms.de/de/meetings/hoch2005/05hoch163.shtml

Veröffentlicht: 8. August 2006

© 2006 Bader et al.
Dieser Artikel ist ein Open Access-Artikel und steht unter den Creative Commons Lizenzbedingungen (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.de). Er darf vervielf&aauml;ltigt, verbreitet und &oauml;ffentlich zug&aauml;nglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.


Gliederung

Text

Angiotensinogen is the natural substrate for renin required for the production of all active peptides of the renin-angiotensin system. The gene coding for angiotensinogen is composed of 5 exons. Exon 2 (Ex2) is with 854 nucleotides (nt) the longest exon and contains the translational start codon, the signal peptide, and the angiotensin I encoding sequence. However, the length of Ex2 by far exceeds the normal length of internal exons in mammalian genes (150-250 nt). Thus, we hypothesized that a splicing enhancer may be necessary to include this exon into mature mRNA. Indeed, by studying the expression of the mouse angiotensinogen (mAOG) gene by RT-PCR and RNase protection assay (RPA) in different tissues, we detected a small portion (<10%) of mAOG-mRNA which lacked Ex2 confirming alternative splicing of this gene. By expressing a full-length mAOG-gene with a viral promoter in COS7 cells followed by RPA analysis, we could detect the appearance of both mRNA isoforms in these cells (70% full-length, 30% truncated). This cell culture system allowed us to localize the putative splicing enhancer within Ex2 responsible for exon inclusion. To this purpose, the mAOG gene was linearized with Sfi I and the exo-endonuclease Bal-31 was used to generate internal deletions of different lengths in Ex2. These truncated mAOG gene clones were again transfected into COS7 cells and expression analysis was made by RPA. Clones containing an Ex2 of less than 200 nt included it into the mature mRNA probably due to the small size. Clones with Ex2 longer than 340 nt excluded it (30% full-length, 70% truncated) as long as nt 102 to 174 were missing in the construct. We conclude that this region contains an exonic splicing enhancer necessary to avoid skipping of the Ex2. Since Ex2 is essential for angiotensinogen function, interfering with this splicing process might be of therapeutic interest.