Ultraviolet-crosslinking reveals specific affinity of eukaryotic initiation factors for Semliki Forest virus mRNA

Abstract

Eukaryotic initiation factors (elF) associate readily with ³²P-labeled Semliki Forest virus (SFV) mRNA in vitro, forming complexes which can be crosslinked by 254 nm ultraviolet irradiation. After ribonuclease digestion, the initiation factors were released and analysed by gel electrophoresis. Autoradiography revealed proteins by virtue of crosslinked ³²P-labeled mRNA fragments, elF-4A, -4B and -4C as well as three subunits of elF-3 could be crosslinked with SFV mRNA. None of these proteins bound to ribosomal RNAs.