Should we kill the messenger? The role of the surveillance complex in translation termination and mRNA turnover

Eukaryotes have evolved conserved mechanisms to rid cells of faulty gene pr oducts that can interfere with cell function. mRNA surveillance is an examp le of a pathway that monitors the translation termination process and promo tes degradation of transcripts harboring premature translation termination codons. Studies on the mechanism of mRNA surveillance in yeast and humans s uggest a common mechanism where a "surveillance complex" monitors the trans lation process and determines whether translation termination has occurred at the correct position within the mRNA. A model will be presented that sug gests that the surveillance complex assesses translation termination by mon itoring the transition of an RNP as it is converted from a nuclear to a cyt oplasmic form during the initial rounds of translation. BioEssays 21.685-69 6, 1999. (C) 1999 John Wiley & Sons, Inc.