Gene transcripts are under extensive posttranscriptional regulation, including the regulation of their stability. A major route for mRNA degradation produces uncapped mRNAs, which can be generated by decapping enzymes, endonucleases, and small RNAs. Profiling uncapped mRNA molecules is important for the understanding of the transcriptome, whose composition is determined by a balance between mRN...

In recent years, the use of genome-wide technologies has revolutionized the study of eukaryotic transcription producing results for thousands of genes at every step of mRNA life. The statistical analyses of the results for a single condition, different conditions, different transcription stages, or even between different techniques, is outlining a totally new landscape of the eukaryotic transcr...

Based on the above mechanisms of mRNA degradation, an integrated model of mRNA turnover can be proposed (Figure 1). In this model, all polyadenylated mRNAs would be degraded by the deadenylation-dependent pathway at some rate. In addition to this default pathway, another layer of complexity would come from degradation mechanisms specific to individual mRNAs or to classes of mRNAs. Such mRNA-spe...

Early in the development of many animals, before transcription begins, any change in the pattern of protein synthesis is attributed to a change in the translational activity or stability of mRNA in the egg and early embryo. As a result, translational control is critical for a variety of developmental decisions, including oocyte maturation and initiation of preimplantation development. In this s...

Cyanobacteria are photosynthetic prokaryotic organisms that share characteristics with bacteria and chloroplasts regarding mRNA degradation. Synechocystis sp. PCC6803 is a model organism for cyanobacteria, but not much is known about the mechanism of RNA degradation. Only one member of the RNase II-family is present in the genome of Synechocystis sp PCC6803. This protein was shown to be essenti...

Infection with gammaherpesviruses, alphaherpesviruses, and betacoronaviruses can result in widespread mRNA degradation, in each case initiated predominantly by a single viral factor. Although not homologous, these factors exhibit significant mechanistic similarities. In cells, each targets translatable RNAs for cleavage and requires host Xrn1 to complete RNA degradation, although the mechanism ...

Escherichia coli contains multiple 3' to 5' RNases, of which two, RNase PH and polynucleotide phosphorylase (PNPase), use inorganic phosphate as a nucleophile to catalyze RNA cleavage. It is known that an absence of these two enzymes causes growth defects, but the basis for these defects has remained undefined. To further an understanding of the function of these enzymes, the degradation patter...

Ring-shaped structures containing seven Sm or Sm-like proteins are stable components of several small nuclear ribonucleoprotein particles that function in pre-mRNA splicing. Recent reports describe a role for a distinct complex of seven Sm-like proteins in a very different process: mRNA degradation.

Nonsense-mediated mRNA decay (NMD) is an mRNA degradation pathway that regulates gene expression and mRNA quality. A complex network of macromolecular interactions regulates NMD initiation, which is only partially understood. According to prevailing models, NMD begins by the assembly of the SURF (SMG1-UPF1-eRF1-eRF3) complex at the ribosome, followed by UPF1 activation by additional factors suc...

In Saccharomyces cerevisiae, rapid degradation of nonsense-containing mRNAs requires the decapping enzyme Dcp1p, the 5'-to-3' exoribonuclease Xrn1p, and the three nonsense-mediated mRNA decay (NMD) factors, Upf1p, Nmd2p, and Upf3p. To identify specific functions for the NMD factors, we analyzed the mRNA decay phenotypes of yeast strains containing deletions of DCP1 or XRN1 and UPF1, NMD2, or UP...