Translational efficiency and competitive ability of mRNAs with 5′-untranslated αβ-leader of potato virus X RNA

• Published in: Biochimie Vol. 73; no. 5; pp. 587 - 598
• Main Authors: Smirnyagina, E.V., Morozov, S.Y., Rodionova, N.P., Miroshnichenko, N.A., Solovyev, A.G., Fedorkin, O.N., Atabekov, J.G.
• Format: Journal Article
• Language: English
• Published: Elsevier Masson SAS 1991
• Subjects: plant virus; recombinant DNA; translational competition; translational enhancement; αβ; eIF; nt; RRL; WG; translational competition; translational enhancement; PVX; TCA; KA; NPT I, II; recombinant DNA; TMV; plant virus
• ISSN: 0300-9084; 1638-6183
• DOI: 10.1016/0300-9084(91)90027-X

The 5′-untranslated leader sequence of potato virus X (PVX) RNA (63 nucleotides apart from cap-structure) consists of two sub-sequences referred to as α-sequence (41 nucleotides with no G) and β-sequence (42 nucleotides upstream from the first AUG). Computer-based folding predictions suggest that the 5′-proximal region of αβ-leader is unstructured. The second structural feature of αβ-leader is the presence of the sequences apparently complementary to the 3′-terminal region of 18S rRNA. The αβ-leader has been shown to strongly enhance the translation of the contiguous foreign gene (NPT1) transcripts in cell-free translation systems from rabbit reticulocytes (RRL), wheat germ (WG) and Krebs-2 ascite cell extract (KA). In competitive translation PVX, RNA strongly inhibited tobacco mosaic virus (TMV) RNA in RRL and WG systems. No competition occurred between PVX and TMV RNAs in KA system. There was no correlation between the translational efficiency and competitive ability of PVX RNA in different cell-free translation systems. The competitive ability did not solely depend on the presence of αβ-leader in mRNA. We present evidence to suggest that αβ-leader together with about 150 bases of the coding sequence is responsible for the translation competitive ability of PVX RNA.