A mediator system is a kind of a meta-search engine that provides a seamlessly integrated search service for diverse search engines (collections). Since collections of a mediator system are geographically distributed, its performance is mainly influenced by the data transmission time between the mediator and its collections. Existing mediator systems employ a result cache that is composed of th...

Transcription is one of the key biological functions of the cell. A tight regulation of this process is extremely important for cell physiology. It is now generally accepted that a large protein complex, the Mediator of transcription regulation, is essential for eukaryotic transcription by RNA polymerase II (Pol II) in response to transcription activators. Unsurprisingly, Mediator has been impl...

RNA polymerase II (Pol II), whose 12 subunits are conserved across eukaryotes, is at the heart of the machinery responsible for transcription of mRNA. Although associated general transcription factors impart promoter specificity, responsiveness to gene- and tissue-selective activators additionally depends on the multiprotein Mediator coactivator complex. We have isolated from tissue extracts a ...

Regulation of HO gene expression in the yeast Saccharomyces cerevisiae is intricately orchestrated by an assortment of gene-specific DNA-binding and non-DNA binding regulators. Binding of the early G1 transcription factor Swi5 to the distal URS1 element of the HO promoter initiates a cascade of events through recruitment of the Swi/Snf and SAGA complexes. In late G1, binding of transcription fa...

A key hub for the orchestration of epigenetic modifications necessary to restrict neuronal gene expression to the nervous system is the RE1 silencing transcription factor (REST; also known as neuron restrictive silencer factor, NRSF). REST suppresses the nonspecific and premature expression of neuronal genes in non-neuronal and neural progenitor cells, respectively, via recruitment of enzymatic...

Mediator was resolved from yeast as a multiprotein complex on the basis of its requirement for transcriptional activation in a fully defined system. Three groups of mediator polypeptides could be distinguished: the products of five SRB genes, identified as suppressors of carboxy-terminal domain (CTD)-truncation mutants; products of four genes identified as global repressors; and six members of ...

This paper describes an active object-oriented mediator for the enforcement of global consistency between relational legacy databases. We discuss the problem of integrating several local relational systems into a federated system by the usage of an object-oriented mediator system. We explore how relational DBMSs can be enhanced to signal local updates that may violate global constraints without...

The Mediator complex has been described as a general transcription factor, but it is unclear if it is essential for Pol II transcription and/or is a required component of the preinitiation complex (PIC) in vivo. Here, we show that depletion of individual subunits, even those essential for cell growth, causes a general but only modest decrease in transcription. In contrast, simultaneous depletio...

Others have shown that yeast strains bearing a ts mutation in the Srb4 subunit of Mediator cease transcription of all mRNA at the restrictive temperature, in a manner virtually indistinguishable from a strain bearing a ts mutation in the largest subunit of RNA polymerase II. We find that srb4ts Mediator is defective for the stimulation of basal RNA polymerase II transcription at the restrictive...