In Arabidopsis, RNA-dependent DNA methylation and transcriptional silencing involves three nuclear RNA polymerases that are biochemically undefined: the presumptive DNA-dependent RNA polymerases Pol IV and Pol V and the putative RNA-dependent RNA polymerase RDR2. Here we demonstrate their RNA polymerase activities in vitro. Unlike Pol II, Pols IV and V require an RNA primer, are insensitive to ...

The eukaryotic RNA polymerases Pol I, II, and III use different promoters to transcribe different classes of genes. Promoter usage relies on initiation factors, including TFIIF and TFIIE, in the case of Pol II. Here, we show that the Pol I-specific subunits A49 and A34.5 form a subcomplex that binds DNA and is related to TFIIF and TFIIE. The N-terminal regions of A49 and A34.5 form a dimerizati...

This review discusses recent insights in the roles of DNA polymerases (Pol) and in eukaryotic DNA replication. A growing body of evidence specifies Pol as the leading strand DNA polymerase and Pol as the lagging strand polymerase during undisturbed DNA replication. New evidence supporting this model comes from the use of polymerase mutants that show an asymmetric mutator phenotype for certain m...

Transcription is defined as the synthesis of RNA from a DNA template. In bacteria, transcription of all genes is catalysed by a single RNA polymerase, whereas in the eukaryotic nucleus, three different RNA polymerases — Pol I, Pol II and Pol III — carry out the synthesis of different classes of RNA. Pol I and Pol III transcribe a limited number of genes encoding ribosomal RNAs, transfer RNAs an...

RNA Pol II elongation in eukaryotes is coupled with a series of histone modifications. Elongating RNA Pol II can be strongly stalled by lesions on the DNA template. However, it is unclear whether RNA Pol II stalling affects elongation-associated histone modifications. We have explored this important question by investigating the function of histone H2B mono-ubiquitylation (H2Bub), a well-charac...

Mutations at the CLAVATA loci (CLV1, CLV2 and CLV3) result in the accumulation of undifferentiated cells at the shoot and floral meristems. We have isolated three mutant alleles of a novel locus, POLTERGEIST (POL), as suppressors of clv1, clv2 and clv3 phenotypes. All pol mutants were nearly indistinguishable from wild-type plants; however, pol mutations provided recessive, partial suppression ...

Biodiesel obtained through the transesterification in methanol of vegetable oils, such as soybean oil (SO) and waste cooking (WCO), cannot be used a biofuel for automotive applications due to presence polyunsaturated fatty esters, which have detrimental effect on oxidation stability (OS). A method upgrading this material is catalytic partial hydrogenation acid methyl ester (FAME) mixture. The t...

SNAP(c) is one of a few basal transcription factors used by both RNA polymerase (pol) II and pol III. To define the set of active SNAP(c)-dependent promoters in human cells, we have localized genome-wide four SNAP(c) subunits, GTF2B (TFIIB), BRF2, pol II, and pol III. Among some seventy loci occupied by SNAP(c) and other factors, including pol II snRNA genes, pol III genes with type 3 promoters...

The efficacy of suicide herpes simplex virus-1 thymidine kinase (HSVtk)/ganciclovir (GCV) gene therapy is often limited by intrinsic resistance of tumor cells. Here we show that repair of GCV incorporated in DNA is a factor involved in GCV resistance. A protective role of DNA repair in GCV-induced cell killing is supported by the following findings: (a) GCV-exposed Chinese hamster ovary-HSVtk c...