Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
3425516 | Virology | 2009 | 12 Pages |
The genome of Red clover necrotic mosaic virus (RCNMV) consists of RNA1 and RNA2, both lacking a cap structure and a poly(A)tail. RNA1 has a translational enhancer element (3′TE-DR1) in the 3′ untranslated region (UTR). In this study, we analyzed the roles of 5′ and 3′ UTRs of RNA1 in 3′TE-DR1-mediated cap-independent translation in cowpea and tobacco BY-2 protoplasts using a dual-luciferase (Luc) reporter assay system. Most mutations introduced into RNA1 5′ UTR in reporter Luc mRNA abolished or greatly reduced cap-independent translation in BY-2 protoplasts, whereas those mutations had no or much milder effects if any on translational activity in cowpea protoplasts. Our results suggest that a stem–loop structure predicted in the 5′ proximal region of RNA1 plays important roles in both translation and RNA stability. We also show that 3′TE-DR1-mediated cap-independent translation relies on a ribosome-scanning mechanism in both protoplasts.