Figure 7.

Binding of the CDV IRES to 40S subunits depending on the presence of eIF3. (A–C) Binding of 40S subunits and 40S/eIF3 complexes to the IRES, assayed by SDG centrifugation. Complexes were assembled by incubating (A) [³²P]UTP-labeled CDV nt 341–1108, or PV mRNA comprising nt 116–632 and 96 nt of the 3D ORF, (B) [³²P]UTP-labeled CDV nt 341–1108, nt 341–920 or nt 518–805 mRNAs (as indicated) and (C) [³²P]UTP-labeled CDV nt 341–805 or nt 2–197 of β-globin mRNA with 40S subunits in the absence and in the presence of eIF3 and PCBP2, as indicated. Sedimentation was from right to left. Upper gradient fractions have been omitted for clarity. (D) Toe-printing analysis of binding of 40S subunits and eIF3 to wt and [d12→dVI] mutant Stem-MC CDV mRNAs. Toe-prints are indicated on the right.