Remarks on the mechanism of ribosome binding to eukaryotic mRNAs.

It is evident from the data discussed here that the mechanism and the rules for mRNA binding in eukaryotes are complex and not well defined. The major points of this review are (1) ribosome binding could be preceded by the unwinding of mRNA secondary structure; (2) there is no obligatory ribosome entry through the 5' end of the mRNA; (3) there is no obligatory linear "scanning" of the 5'UTR; and (4) there are some interesting similarities between prokaryotes and eukaryotes in the mode of ribosome binding to mRNA, particularly in the ability of the small ribosomal subunit to diffuse or "scan" on the mRNA, and in the requirement for a minimally structured RNA for efficient ribosome binding.