Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.6 (RNA polymerase)
 34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The multiprotein Mediator complex is a coactivator required for activation of RNA polymerase II transcription by DNA bound transcription factors. We previously identified and partially purified a mammalian Mediator complex from rat liver nuclei (Brower, C.S., Sato, S., Tomomori-Sato, C., Kamura, T., Pause, A., Stearman, R., Klausner, R.D., Malik, S., Lane, W.S., Sorokina, I., Roeder, R.G., Conaway, J.W., and Conaway, R.C. (2002) Proc. Natl. Acad. Sci. U. S. A. 99, 10353-10358). Analysis by tandem mass spectrometry of proteins present in the most highly purified rat Mediator fractions led to the identification of a collection of new mammalian Mediator subunits, as well as several potential Mediator subunits including a previously uncharacterized protein encoded by the FLJ10193 open reading frame. In this study, we present direct biochemical evidence that the FLJ10193 protein, which we designate Med25, is a bona fide subunit of the mammalian Mediator complex. In addition, we present evidence that Med25 shares structural and functional properties with Saccharomyces cerevisiae Mediator subunit Cse2 and may be a mammalian Cse2 ortholog. Taken together, our findings identify a novel mammalian Mediator subunit and shed new light on the architecture of the mammalian Mediator complex.
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PMID:A mammalian mediator subunit that shares properties with Saccharomyces cerevisiae mediator subunit Cse2. 1463 76

The Mediator is a multiprotein transcriptional coactivator that is expressed ubiquitously in eukaryotes from yeast to mammals and is required for induction of RNA polymerase II (pol II) transcription by DNA binding transcription factors. In the work described here, we exploit multidimensional protein identification technology (MudPIT) to carry out a proteomic analysis of the subunit composition of the mammalian Mediator complex. By comparing MudPIT data sets obtained from six independent Mediator preparations immunoaffinity purified through their Nut2 (MED10), Med25 (MED9), Intersex (MED29), LCMR1 (MED19), AK007855 (MED28), or CRSP70 (MED26) subunits, we identify a set of consensus mammalian Mediator subunits. In addition, we identify as Mediator-associated proteins the CDK8-like cyclin-dependent kinase CDK11 and the TRAP240-like KIAA1025 protein (MED13L), which is mutated in patients with the congenital heart defect transposition of the great arteries (TGA).
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PMID:A set of consensus mammalian mediator subunits identified by multidimensional protein identification technology. 1517 63

Brassinosteroids (BRs) are plant-specific steroid hormones which regulate plant growth, development, and adaptation. Transcriptional regulation plays key roles in plant hormone signaling. A mediator can serve as a bridge between gene-specific transcription factors and the RNA polymerase machinery, functioning as an essential component in regulating the transcriptional process. However, whether a mediator is involved in BR signaling is unknown. Here, we discovered that Oryza sativa mediator subunit 25 (OsMED25) is an important regulator of rice BR signaling. Phenotypic analyses showed that the OsMED25-RNAi and osmed25 mutant presented erect leaves, as observed in BR-deficient mutants. In addition, the OsMED25-RNAi and osmed25 mutant exhibited decreased BR sensitivity. Genetic analysis indicated that OsMED25-RNAi could suppress the enhanced BR signaling phenotype of Osbzr1-D. Further biochemical analysis showed that OsMED25 interacts with OsBZR1 in vivo, and OsMED25 is enriched on the promoter of OsBZR1 target genes. RNA sequencing analysis indicated that OsMED25 affects the expression of approximately 45% of OsBZR1-regulated genes and mainly functions as a corepressor of OsBZR1. Together, these findings revealed that OsMED25 regulates rice BR signaling by interacting with OsBZR1 and modulating the expression of OsBZR1 target genes, thus expanding our understanding of the roles of mediators in plant hormone signaling.
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PMID:Oryza sativa mediator subunit OsMED25 interacts with OsBZR1 to regulate brassinosteroid signaling and plant architecture in rice. 3199 Jan 25