Gene 61.5 of bacteriophage T4 has a unique role in gene expression. When this gene is mutated, mRNAs of many late genes are rapidly degraded, resulting in late-gene silencing. Here, we characterize an extragenic suppressor, ssf5, of a gene 61.5 mutation. ssf5 was found to be an amber mutation in motA, which encodes a transcription activator for T4 middle genes. When this gene is mutated, both d...

The 5'-to-3' mRNA degradation machinery localizes to cytoplasmic processing bodies (P-bodies), which are non-membranous structures found in all eukaryotes. Although P-body function has been intensively studied in yeast, less is known about their role in mammalian cells, such as whether P-body enzymes are actively engaged in mRNA degradation or whether P-bodies serve as mRNA storage depots, part...

Ultraconserved elements, unusually long regions of perfect sequence identity, are found in genes encoding numerous RNA-binding proteins including arginine-serine rich (SR) splicing factors. Expression of these genes is regulated via alternative splicing of the ultraconserved regions to yield mRNAs that are degraded by nonsense-mediated mRNA decay (NMD), a process termed unproductive splicing (L...

Several thousand human genes, amounting to about one-third of the whole genome, are potential targets for regulation by the several hundred microRNAs (miRNAs) encoded in the genome. The regulation occurs posttranscriptionally and involves the approximately 21-nucleotide miRNA interacting with a target site in the mRNA that generally has imperfect complementarity to the miRNA. The target sites a...

The major coat protein of the L-A double-stranded RNA virus of Saccharomyces cerevisiae covalently binds m7 GMP from 5' capped mRNAs in vitro. We show that this cap binding also occurs in vivo and that, while this activity is required for expression of viral information (killer toxin mRNA level and toxin production) in a wild-type strain, this requirement is suppressed by deletion of SKI1/XRN1/...

P-bodies are cytoplasmic foci that are sites of mRNA degradation and translational repression. It is not known what causes the accumulation of RNA-degradation factors in P-bodies, although RNA is required. The yeast Lsm1-7p complex (comprising Lsm1p to Lsm7p) is recruited to P-bodies under certain stress conditions. It is required for efficient decapping and degradation of mRNAs, but not for th...