mRNA stability: in trans-it.

The regulation of mRNA stability is an important step in the control of gene expression. Characterization of the mechanisms involved in the turnover of individual mRNAs has identified a requirement for specific cis-acting sequences and trans-acting factors, as well as an involvement of the translation apparatus. In the past year, significant progress has been made in the identification of trans-acting factors by both biochemical and genetic approaches. This review summarizes that progress and promotes the notion that the ribosome itself should also be considered as a trans-acting component of the mRNA decay machinery.