Stewart Shuman

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Epstein-Barr virus (EBV or HHV4), a member of the human herpesvirus (HHV) family, has recently been shown to encode microRNAs (miRNAs). In contrast to most eukaryotic miRNAs, these viral miRNAs do not have close homologs in other viral genomes or in the genome of the human host. To identify other miRNA genes in pathogenic viruses, we combined a new miRNA(More)
The C-terminal heptad repeat domain (CTD) of RNA polymerase II (pol II) is proposed to target pre-mRNA processing enzymes to nascent pol II transcripts, but this idea has not been directly tested in vivo. In vitro, the yeast mRNA capping enzymes Ceg1 and Abd1 bind specifically to the phosphorylated CTD. Here we show that yeast capping enzymes cross-link in(More)
Capping is targeted to pre-mRNAs through binding of the guanylyltransferase component of the capping apparatus to the phosphorylated CTD of RNA polymerase II. We report that mammalian guanylyltransferase binds synthetic CTD peptides containing phosphoserine at either position 2 or 5 of the YSPTSPS heptad repeat. CTD peptides containing Ser-5-PO4 stimulate(More)
mRNA capping entails GMP transfer from GTP to a 5' diphosphate RNA end to form the structure G(5')ppp(5')N. A similar reaction involving AMP transfer to the 5' monophosphate end of DNA or RNA occurs during strand joining by polynucleotide ligases. In both cases, nucleotidyl transfer occurs through a covalent lysyl-NMP intermediate. Sequence conservation(More)
We have solved the crystal structure of an mRNA capping enzyme at 2.5 A resolution. The enzyme comprises two domains with a deep, but narrow, cleft between them. The two molecules in the crystallographic asymmetric unit adopt very different conformations; both contain a bound GTP, but one protein molecule is in an open conformation while the other is in a(More)
The ts49 mutation of vaccinia virus WR was mapped by marker rescue to the E11 gene encoding a 15-kDa polypeptide. During synchronous infection of BSC40 cells with wild-type virus, immunoreactive E11 protein accumulated in parallel with the onset of late protein synthesis. Immunoblotting of extracts of wild-type virions showed that the E11 protein was(More)
Mammalian cells have three ATP-dependent DNA ligases, which are required for DNA replication and repair. Homologues of ligase I (Lig1) and ligase IV (Lig4) are ubiquitous in Eukarya, whereas ligase III (Lig3), which has nuclear and mitochondrial forms, appears to be restricted to vertebrates. Lig3 is implicated in various DNA repair pathways with its(More)
We have investigated the role of the RNA Polymerase II (Pol II) carboxy-terminal domain (CTD) in mRNA 5' capping. Transcripts made in vivo by Pol II with a truncated CTD had a lower proportion of capped 5' ends than those made by Pol II with a full-length CTD. In addition, the enzymes responsible for cap synthesis, RNA guanylyltransferase, and RNA(More)
The carboxyl-terminal domain (CTD) of elongating RNA polymerase II serves as a landing pad for macromolecular assemblies that regulate mRNA synthesis and processing. The capping apparatus is the first of the assemblies to act on the nascent pre-mRNA and the one for which binding of the catalytic components is most clearly dependent on CTD phosphorylation.(More)