[1] Univ Newcastle Upon Tyne, Sch Med, Inst Cell & Mol Biosci, Newcastle Upon Tyne NE2 4HH, Tyne & Wear, England
[2] Univ Newcastle Upon Tyne, Sch Med, RNA Biol Grp, Newcastle Upon Tyne NE2 4HH, Tyne & Wear, England
[3] Oregon Hlth & Sci Univ, Dept Environm & Biomol Syst, Beaverton, OR 97006 USA
[4] Univ St Andrews, Ctr Biomol Sci, Sch Biol, St Andrews KY16 9ST, Fife, Scotland
[5] Oregon Hlth & Sci Univ, Dept Mol Microbiol & Immunol, Portland, OR 97201 USA