First two authors have contributed equally to the work.
Ribosome readthrough accounts for secreted full-length factor IX in hemophilia B patients with nonsense mutations†
Article first published online: 11 JUN 2012
© 2012 Wiley Periodicals, Inc.
Special Issue: Databases in Neurogenetics
Volume 33, Issue 9, pages 1373–1376, September 2012
How to Cite
Pinotti, M., Caruso, P., Canella, A., Campioni, M., Tagariello, G., Castaman, G., Giacomelli, S., Belvini, D. and Bernardi, F. (2012), Ribosome readthrough accounts for secreted full-length factor IX in hemophilia B patients with nonsense mutations. Hum. Mutat., 33: 1373–1376. doi: 10.1002/humu.22120
Communicated by John McVey
- Issue published online: 13 AUG 2012
- Article first published online: 11 JUN 2012
- Accepted manuscript online: 15 MAY 2012 11:17AM EST
- Manuscript Accepted: 7 MAY 2012
- Manuscript Received: 17 JAN 2012
- University of Ferrara, Telethon, Italy. Grant Number: GGP09183
- Fondazione CARIFE; Ministero dell'Università e della Ricerca (MIUR)—Progetti di Ricerca di Interesse Nazionale (PRIN); AIFA (AIFA 2008—Bando per le malattie rare—Progetto RF-null-2008-1235892)
- nonsense mutations;
- coagulation factor;
We investigated the spontaneous ribosome readthrough, virtually unexplored in genes encoding secreted proteins, over coagulation F9 nonsense mutations. Expression of recombinant factor IX (FIX) in eukaryotic cells demonstrated appreciable levels of secreted FIX molecules for the mutations p.R162* (5 ± 0.3% of rFIX-wt antigen levels), p.R294* (3.1 ± 1.1%) and p.R298* (2.5 ± 0.7%), but not for the p.L103*. Western blotting revealed a large proportion of truncated molecules, which correlated with small amounts of full-length FIX (rFIX-162*, ∼0.5%; rFIX-294*; and rFIX-298*, ∼0.2%). Western blotting of plasma from FIX deficient (Hemophilia B) patients revealed traces of full-length FIX for the p.R294* and p.R298* mutations, but not for the p.L103* mutation that triggered major FIX mRNA decay. The detection of full-length proteins has clinical implication, particularly for post-therapeutic immunological complications in Hemophilia. Data in patients' plasma and in vitro, obtained in the proper protein context, support a ribosome readthrough gradient, consistent with its predicted determinants of efficiency. Hum Mutat 33:1373–1376, 2012. © 2012 Wiley Periodicals, Inc.