Component of the Mediator complex, a coactivator involved in the regulated transcription of nearly all RNA polymerase II-dependent genes. Mediator functions as a bridge to convey information from gene-specific regulatory proteins to the basal RNA polymerase II transcription machinery. Mediator is recruited to promoters by direct interactions with regulatory proteins and serves as a scaffold for the assembly of a functional preinitiation complex with RNA polymerase II and the general transcription factors.
Catalysis of the reaction: nucleoside triphosphate + RNA(n) = diphosphate + RNA(n+1). Utilizes a DNA template, i.e. the catalysis of DNA-template-directed extension of the 3'-end of an RNA strand by one nucleotide at a time. Can initiate a chain 'de novo'.
J. Biol. Chem. 274, 3937-3940 (1999)[PubMed:9933582]
Mammalian RNA polymerase II holoenzymes are large complexes that have been reported to contain, in addition to RNA polymerase II, homologues of several yeast SRBs, various general transcription factors, and other polypeptides. On the basis of its copurification with an SRB-containing RNA polymerase II complex by conventional chromatography procedures, we have identified a human homologue of Drosophila TRF-proximal protein, designated hTRFP, and isolated its cognate cDNA. Antibody specific for SRB7 can immunoprecipitate hTRFP and RNA polymerase II and, reciprocally, antibody specific for hTRFP can immunoprecipitate RNA polymerase II and SRB7. These data indicate that hTRFP is an integral component of an RNA polymerase II-SRB complex. Whereas the precise function of hTRFP remains to be determined, the hTRFP-containing RNA polymerase II-SRB complex supports basal level transcription and, relative to RNA polymerase II alone, enhances transcriptional activation by Gal4-VP16 in the presence of cofactor PC4. Thus, hTRFP may regulate transcription of class II genes through association with the RNA polymerase II-SRB complex.
Interacting selectively and non-covalently with any protein or protein complex (a complex of two or more proteins that may include other nonprotein molecules).
Evidence
1:
Inferred from Physical InteractionIntAct
The multiprotein Mediator complex is a coactivator required for transcriptional activation of RNA polymerase II transcribed genes by DNA binding transcription factors. We previously partially purified a Med8-containing 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 of proteins present in the most highly enriched Mediator fractions by tandem mass spectrometry led to the identification of several new mammalian Mediator subunits, as well as several potential Mediator subunits. Here we identify one of these proteins, encoded by the previously uncharacterized AK000411 open reading frame, as a new subunit of the mammalian Mediator complex. The AK000411 protein, which we designate hIntersex (human Intersex), shares significant sequence similarity with the Drosophila melanogaster intersex protein, which has functional properties expected of a transcriptional coactivator specific for the Drosophila doublesex transactivator. In addition, we show that hIntersex assembles into a subcomplex with Mediator subunits p28b and TRFP. Taken together, our findings identify a new subunit of the mammalian Mediator and shed new light on the architecture of the mammalian Mediator complex.
Evidence
2:
Inferred from Physical InteractionIntAct
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).
Interacting selectively and non-covalently with an RNA polymerase II (RNAP II) regulatory transcription factor and also with the RNAP II basal transcription machinery in order to modulate transcription. Cofactors generally do not bind DNA, but rather mediate protein-protein interactions between regulatory transcription factors and the basal RNAP II transcription machinery.
J. Biol. Chem. 274, 3937-3940 (1999)[PubMed:9933582]
Mammalian RNA polymerase II holoenzymes are large complexes that have been reported to contain, in addition to RNA polymerase II, homologues of several yeast SRBs, various general transcription factors, and other polypeptides. On the basis of its copurification with an SRB-containing RNA polymerase II complex by conventional chromatography procedures, we have identified a human homologue of Drosophila TRF-proximal protein, designated hTRFP, and isolated its cognate cDNA. Antibody specific for SRB7 can immunoprecipitate hTRFP and RNA polymerase II and, reciprocally, antibody specific for hTRFP can immunoprecipitate RNA polymerase II and SRB7. These data indicate that hTRFP is an integral component of an RNA polymerase II-SRB complex. Whereas the precise function of hTRFP remains to be determined, the hTRFP-containing RNA polymerase II-SRB complex supports basal level transcription and, relative to RNA polymerase II alone, enhances transcriptional activation by Gal4-VP16 in the presence of cofactor PC4. Thus, hTRFP may regulate transcription of class II genes through association with the RNA polymerase II-SRB complex.
The synthesis of RNA from a DNA template by RNA polymerase II, originating at an RNA polymerase II promoter. Includes transcription of messenger RNA (mRNA) and certain small nuclear RNAs (snRNAs).
J. Biol. Chem. 274, 3937-3940 (1999)[PubMed:9933582]
Mammalian RNA polymerase II holoenzymes are large complexes that have been reported to contain, in addition to RNA polymerase II, homologues of several yeast SRBs, various general transcription factors, and other polypeptides. On the basis of its copurification with an SRB-containing RNA polymerase II complex by conventional chromatography procedures, we have identified a human homologue of Drosophila TRF-proximal protein, designated hTRFP, and isolated its cognate cDNA. Antibody specific for SRB7 can immunoprecipitate hTRFP and RNA polymerase II and, reciprocally, antibody specific for hTRFP can immunoprecipitate RNA polymerase II and SRB7. These data indicate that hTRFP is an integral component of an RNA polymerase II-SRB complex. Whereas the precise function of hTRFP remains to be determined, the hTRFP-containing RNA polymerase II-SRB complex supports basal level transcription and, relative to RNA polymerase II alone, enhances transcriptional activation by Gal4-VP16 in the presence of cofactor PC4. Thus, hTRFP may regulate transcription of class II genes through association with the RNA polymerase II-SRB complex.
J. Biol. Chem. 274, 3937-3940 (1999)[PubMed:9933582]
Mammalian RNA polymerase II holoenzymes are large complexes that have been reported to contain, in addition to RNA polymerase II, homologues of several yeast SRBs, various general transcription factors, and other polypeptides. On the basis of its copurification with an SRB-containing RNA polymerase II complex by conventional chromatography procedures, we have identified a human homologue of Drosophila TRF-proximal protein, designated hTRFP, and isolated its cognate cDNA. Antibody specific for SRB7 can immunoprecipitate hTRFP and RNA polymerase II and, reciprocally, antibody specific for hTRFP can immunoprecipitate RNA polymerase II and SRB7. These data indicate that hTRFP is an integral component of an RNA polymerase II-SRB complex. Whereas the precise function of hTRFP remains to be determined, the hTRFP-containing RNA polymerase II-SRB complex supports basal level transcription and, relative to RNA polymerase II alone, enhances transcriptional activation by Gal4-VP16 in the presence of cofactor PC4. Thus, hTRFP may regulate transcription of class II genes through association with the RNA polymerase II-SRB complex.
Protein involved in the transfer of genetic information from DNA to messenger RNA (mRNA) by DNA-directed RNA polymerase. In the case of some RNA viruses, protein involved in the transfer of genetic information from RNA to messenger RNA (mRNA) by RNA-directed RNA polymerase.
A reference proteome is a set of protein sequences derived from a complete proteome which constitutes a defined standard for a particular user community. Reference proteomes are manually defined according to a number of criteria. They cover the proteomes of well- studied model organisms and other proteomes of interest for biomedical and biotechnological research. Reference proteomes have been selected to provide broad coverage of the tree of life, and constitute a representative cross-section of the taxonomic diversity to be found within UniProtKB.
My favorites 
My labels 
Login
