Uridylation: a vital way for cellular RNA surveillance.

RNA uridylation is an efficient posttranscriptional regulator of gene expression conserved in almost all eukaryotes. Terminal uridylyltransferase (TUTase) are responsible for monouridylation and oligouridylation of various RNA substrates, including snRNA, miRNA, mRNA and other ncRNAs. Studies have demonstrated that monouridylation on ncRNA intermediates alters their ultimate products and processing rates, whereas oligouridylation is often employed to degrade particular RNAs with spatio-temporal specificity and responsible for clearance of the aberrant RNAs and viral RNAs. Uridylation regulates gene expression by these two ways, therefore affects several important biological processes including organismal reproduction and early development, apoptosis, tumorigenesis, as well as virus infection. In this review, we provide the summarization of current researches on uridylation, introduce several techniques widely used for RNA 3' terminus detection, put more emphases on describing the mechanisms of how uridylation controls gene expression, and summarize the key roles of uridylation in RNA surveillance and several biological processes. Furthermore, we discuss other unsolved issues and crucial aspects of future research as well, with the aim of providing new ideas for anti-tumor and anti-virus therapies.