A novel mediator between activator proteins and the RNA polymerase II transcription apparatus

Kelleher, Raymond J.; Flanagan, Peter M.; Kornberg, Roger D.

doi:10.1016/0092-8674(90)90685-8

Cited by 414 publications

(282 citation statements)

References 25 publications

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“…To create pSK113, pGAL4CG-(23) was digested with Xho I and Sma I, and the liberated CYCI promoter-G-free cassette fusion was cloned into the Xho I and Xba I (blunt-ended by the Klenow fragment) sites of pGEM-7Zf(+) (Stratagene). The 5' end of the CYCI promoter of pSK113 is nucleotide position -138 with respect to the translation initiation site at +1 (24). pSK114 was constructed by replacing the Xho I-Ava II region (from -138 to -68) of pSK113 with the Xho I-Ava II fragment (from -248 to -68) ofthe authentic CYCI promoter (24).…”

Section: Methodsmentioning

confidence: 99%

“…It is conceivable that the DNAbinding proteins exert their effects either through intermediary factors termed coactivators (sometimes called mediators or adaptors) or directly on the general transcription factors (4). Candidates for coactivators, which are required for the activator-induced transcription but not for the basal transcription, have been identified in yeast (5)(6)(7)(8)(9) and mammalian cells (10)(11)(12)(13).…”

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confidence: 99%

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Yeast GAL11 protein is a distinctive type transcription factor that enhances basal transcription in vitro.

Sakurai

Hiraoka

Fukasawa

1993

Proc. Natl. Acad. Sci. U.S.A.

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The yeast auxiliary transcription factor GAL1l, a candidate for the coactivator, was partially purified from yeast cells, and its function was characterized in a cell-free ranscription system. The partially purified GAL1l protein stimulated basal transcription from the CYCI core promoter by a factor of 4-5 at the step of preinitiation complex formation. GALll protein also enhanced transcription activated by general regulatory factor 1, GAL4-AH, or GAL4-VP16 to the same extent as the basal ranscription. Therefore, the apparent potentiation of the activators by GALll was attributable to the stimulation of basal transcription. The wild-type GALll protein (but not a mutant-type protein) produced in bacteria stimulated transcription as effectively as GAL1l from yeast. These results suggest that GALll functions as a positive cofactor of basal and activator-induced transcription in a cell-free transcription system. that potentiates a weak activator GAL4-AH. Surprisingly, the mutation is a missense mutation within GALI and was therefore designated GALIIP (P stands for potentiator). They suggest a direct interaction between GAL1l and GAL4 molecules and suggest that the complex of the two proteins is a strong activator. They further find that GALII is required for normal functioning of PPR1, an activator for the URA3 gene. Puzzlingly, GALI is also involved in the transcriptional repression of genes, since a loss-of-function mutation of GALII, called sptl3, restores the transcription of genes inactivated by insertion of the yeast transposon Ty (22).To get insight into the complex pleiotrophic functions of GALH in vivo, we analyzed the role of GAL1l biochemically. We have partially purified GALli protein and studied how it works in a cell-free transcription system. We have found that GAL1l enhances the basal transcription as well as the transcription activated by GAL4-AH, GAL4-VP16, or GRF1. These results suggest that, since GAL1l regulates the basal transcription, it is not a bona fide coactivator, but rather it belongs to a distinctive class of basal transcription factors. (15,27). The major start site of GALli mRNA was Abbreviations: UAS, upstream activation sequence; GRF1, general regulatory factor 1; GST, glutathione S-transferase. MATERIALS AND METHODSITo whom reprint requests should be addressed. 8382

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Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

Yeast GAL11 protein is a distinctive type transcription factor that enhances basal transcription in vitro.

Sakurai

Hiraoka

Fukasawa

1993

Proc. Natl. Acad. Sci. U.S.A.

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“…Single transformants were grown on minimal media supplemented with all required amino acids except leucine and tryptophan as described (24). Whole cell extracts were prepared and assayed for ␤-galactosidase activity as described (26).…”

Section: : 5ј-atatctcgaggatccttytgnacytcnccnccmentioning

confidence: 99%

Genes For Tfb2, Tfb3, and Tfb4 Subunits of Yeast Transcription/Repair Factor IIH

Feaver

Henry

Wang

et al. 1997

Journal of Biological Chemistry

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Genes for the Tfb2, Tfb3, and Tfb4 subunits of yeast RNA polymerase transcription factor IIH (TFIIH) are described. All three genes are essential for cell viability, and antibodies against Tfb3 specifically inhibit transcription in vitro. A C-terminal deletion of Tfb2 caused a defect in nucleotide excision repair, as shown by UV sensitivity of the mutant strain and loss of nucleotide excision repair activity in cell extracts (restored by the addition of purified TFIIH). An interaction between Tfb3 and the Kin28 subunit of TFIIH was detected by the two-hybrid approach, consistent with a role for Tfb3 in linking kinase and core domains of the factor. The deduced amino acid sequence of Tfb2 is similar to that of the 52-kDa subunit of human TFIIH, while Tfb3 is identified as a RING finger protein homologous to the 36-kDa subunit of murine CAK (cyclin-dependent kinase activating kinase) and to the 32-kDa subunit of human TFIIH. Tfb4 is homologous to p34 of human TFIIH and is identified as the weakly associated 37-kDa subunit of the yeast factor. These and other findings reveal a oneto-one correspondence and high degree of sequence similarity between the entire set of yeast and human TFIIH polypeptides.

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“…Mediator (Med) is a multiprotein complex that acts as an interface to pass on the message from the TFs to the basal transcriptional unit assembled at the core promoter, bringing about either transcriptional activation or repression (Bjö rklund and Gustafsson, 2005;Conaway et al, 2005b;Kornberg, 2005). Discovered in the budding yeast Saccharomyces cerevisiae, for its ability to respond to a transcriptional activator (Kelleher et al, 1990;Flanagan et al, 1991), Med was later shown to participate in the transcription of a majority of yeast genes (Holstege et al, 1998).…”

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confidence: 99%

The Mediator Complex in Plants: Structure, Phylogeny, and Expression Profiling of Representative Genes in a Dicot (Arabidopsis) and a Monocot (Rice) during Reproduction and Abiotic Stress

et al. 2011

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The Mediator (Med) complex relays regulatory information from DNA-bound transcription factors to the RNA polymerase II in eukaryotes. This macromolecular unit is composed of three core subcomplexes in addition to a separable kinase module. In this study, conservation of Meds has been investigated in 16 plant species representing seven diverse groups across the plant kingdom. Using Hidden Markov Model-based conserved motif searches, we have identified all the known yeast/metazoan Med components in one or more plant groups, including the Med26 subunits, which have not been reported so far for any plant species. We also detected orthologs for the Arabidopsis (Arabidopsis thaliana) Med32, -33, -34, -35, -36, and -37 in all the plant groups, and in silico analysis identified the Med32 and Med33 subunits as apparent orthologs of yeast/metazoan Med2/ 29 and Med5/24, respectively. Consequently, the plant Med complex appears to be composed of one or more members of 34 subunits, as opposed to 25 and 30 members in yeast and metazoans, respectively. Despite low similarity in primary Med sequences between the plants and their fungal/metazoan partners, secondary structure modeling of these proteins revealed a remarkable similarity between them, supporting the conservation of Med organization across kingdoms. Phylogenetic analysis between plant, human, and yeast revealed single clade relatedness for 29 Med genes families in plants, plant Meds being closer to human than to yeast counterparts. Expression profiling of rice (Oryza sativa) and Arabidopsis Med genes reveals that Meds not only act as a basal regulator of gene expression but may also have specific roles in plant development and under abiotic stress conditions.

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A novel mediator between activator proteins and the RNA polymerase II transcription apparatus

Cited by 414 publications

References 25 publications

Yeast GAL11 protein is a distinctive type transcription factor that enhances basal transcription in vitro.

Yeast GAL11 protein is a distinctive type transcription factor that enhances basal transcription in vitro.

Genes For Tfb2, Tfb3, and Tfb4 Subunits of Yeast Transcription/Repair Factor IIH

The Mediator Complex in Plants: Structure, Phylogeny, and Expression Profiling of Representative Genes in a Dicot (Arabidopsis) and a Monocot (Rice) during Reproduction and Abiotic Stress

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