Gene Symbol: SRB2
Description: Srb2p
Alias: HRS2, MED20, Srb2p
Species: Saccharomyces cerevisiae S288c

Top Publications

  1. Lorch Y, Beve J, Gustafsson C, Myers L, Kornberg R. Mediator-nucleosome interaction. Mol Cell. 2000;6:197-201 pubmed
    ..Sequence alignment shows significant similarity of Nut1 to the GCN5-related N-acetyltransferase superfamily. Finally, recombinant Nut1 exhibits HAT activity in an in-gel assay. ..
  2. Myers L, Gustafsson C, Bushnell D, Lui M, Erdjument Bromage H, Tempst P, et al. The Med proteins of yeast and their function through the RNA polymerase II carboxy-terminal domain. Genes Dev. 1998;12:45-54 pubmed
    ..Evidence for human homologs of several mediator proteins, including Med7, points to similar mechanisms in higher cells. ..
  3. Li Y, Bjorklund S, Jiang Y, Kim Y, Lane W, Stillman D, et al. Yeast global transcriptional regulators Sin4 and Rgr1 are components of mediator complex/RNA polymerase II holoenzyme. Proc Natl Acad Sci U S A. 1995;92:10864-8 pubmed
    ..Taken together with the previous genetic evidence, our findings point to a role of the mediator in repression as well as in transcriptional activation. ..
  4. Takagi Y, Calero G, Komori H, Brown J, Ehrensberger A, Hudmon A, et al. Head module control of mediator interactions. Mol Cell. 2006;23:355-64 pubmed
    ..The head module evidently controls Mediator-RNA polymerase II and Mediator-promoter interactions. ..
  5. Cai G, Imasaki T, Takagi Y, Asturias F. Mediator structural conservation and implications for the regulation mechanism. Structure. 2009;17:559-67 pubmed publisher
    ..This suggests that the topology and structural dynamics of Mediator constitute important elements of a conserved regulation mechanism. ..
  6. Li L, Quinton T, Miles S, Breeden L. Genetic interactions between mediator and the late G1-specific transcription factor Swi6 in Saccharomyces cerevisiae. Genetics. 2005;171:477-88 pubmed
    ..A truncated form of the essential Srb7 mediator subunit also suppresses swi6 mutations and shows a defect in recruitment of the tail module components Sin4, Pgd1, and Gal11 to the mediator complex. ..
  7. Lee Y, Kim Y. Requirement for a functional interaction between mediator components Med6 and Srb4 in RNA polymerase II transcription. Mol Cell Biol. 1998;18:5364-70 pubmed
    ..Our results suggest not only the existence of a specific interaction between Med6 and Srb4 but also the requirement of this interaction in transcriptional regulation of RNA polymerase II holoenzyme. ..
  8. Imasaki T, Calero G, Cai G, Tsai K, Yamada K, Cardelli F, et al. Architecture of the Mediator head module. Nature. 2011;475:240-3 pubmed publisher
    ..Our results reveal architectural principles underlying the role of Mediator in the regulation of gene expression. ..
  9. Koh S, Ansari A, Ptashne M, Young R. An activator target in the RNA polymerase II holoenzyme. Mol Cell. 1998;1:895-904 pubmed
    ..The physiological relevance of this interaction is confirmed by mutations in SRB4, which occur within its GAL4-binding domain and which restore activation in vivo by a GAL4 derivative bearing a mutant activation domain. ..

More Information


  1. Lee Y, Park J, Min S, Han S, Kim Y. An activator binding module of yeast RNA polymerase II holoenzyme. Mol Cell Biol. 1999;19:2967-76 pubmed
  2. Lariviere L, Geiger S, Hoeppner S, Röther S, Strasser K, Cramer P. Structure and TBP binding of the Mediator head subcomplex Med8-Med18-Med20. Nat Struct Mol Biol. 2006;13:895-901 pubmed
    ..Here we show that the head subunits Med8, Med18 and Med20 form a subcomplex (Med8/18/20) with two submodules...
  3. Thompson C, Koleske A, Chao D, Young R. A multisubunit complex associated with the RNA polymerase II CTD and TATA-binding protein in yeast. Cell. 1993;73:1361-75 pubmed
    ..cerevisiae RNA polymerase II CTD truncation mutations led us to identify SRB2, SRB4, SRB5, and SRB6 as genes involved in CTD function in vivo...
  4. Lariviere L, Seizl M, van Wageningen S, Röther S, van de Pasch L, Feldmann H, et al. Structure-system correlation identifies a gene regulatory Mediator submodule. Genes Dev. 2008;22:872-7 pubmed publisher
    ..Deletion of med8C, med18, or med20 causes similar changes in the yeast transcriptome, establishing Med8C/18/20 as a predominantly positive, gene-..
  5. Peng J, Zhou J. The tail-module of yeast Mediator complex is required for telomere heterochromatin maintenance. Nucleic Acids Res. 2012;40:581-93 pubmed publisher
    ..Our study reveals a specific role of Mediator complex at the heterochromatic telomere and this function is specific to telomeres as it has no effect on the HMR locus. ..
  6. Han S, Lee Y, Gim B, Ryu G, Park S, Lane W, et al. Activator-specific requirement of yeast mediator proteins for RNA polymerase II transcriptional activation. Mol Cell Biol. 1999;19:979-88 pubmed
  7. Baidoobonso S, Guidi B, Myers L. Med19(Rox3) regulates Intermodule interactions in the Saccharomyces cerevisiae mediator complex. J Biol Chem. 2007;282:5551-9 pubmed
    ..Although the Middle module is unnecessary for holding the Head and Tail modules together, it is required for the complex to function as a conduit between activators and the core transcription machinery. ..
  8. Takahashi H, Kasahara K, Kokubo T. Saccharomyces cerevisiae Med9 comprises two functionally distinct domains that play different roles in transcriptional regulation. Genes Cells. 2009;14:53-67 pubmed publisher
    ..Add-back experiments indicate that some unidentified factor(s) in med9 extracts may impact the binding of TFIID to the promoter. ..
  9. Kim Y, Bjorklund S, Li Y, Sayre M, Kornberg R. A multiprotein mediator of transcriptional activation and its interaction with the C-terminal repeat domain of RNA polymerase II. Cell. 1994;77:599-608 pubmed
    ..including the three subunits of TFIIF and other polypeptides cross-reactive with antisera against GAL11, SUG1, SRB2, SRB4, SRB5, and SRB6 proteins...
  10. Natarajan K, Jackson B, Zhou H, Winston F, Hinnebusch A. Transcriptional activation by Gcn4p involves independent interactions with the SWI/SNF complex and the SRB/mediator. Mol Cell. 1999;4:657-64 pubmed
  11. Santos Rosa H, Aguilera A. Isolation and genetic analysis of extragenic suppressors of the hyper-deletion phenotype of the Saccharomyces cerevisiae hpr1 delta mutation. Genetics. 1995;139:57-66 pubmed
    ..The mutations eliminated the hyper-deletion phenotype of hpr1 delta strains either completely (hrs1-1 and hrs2-1) or significantly (hrs3-1, hrs4-1 and hrs5-1)...
  12. Costa P, Arndt K. Synthetic lethal interactions suggest a role for the Saccharomyces cerevisiae Rtf1 protein in transcription elongation. Genetics. 2000;156:535-47 pubmed
    ..Collectively, our results suggest that Rtf1 may function as a novel transcription elongation factor in yeast. ..
  13. Roberts S, Winston F. Essential functional interactions of SAGA, a Saccharomyces cerevisiae complex of Spt, Ada, and Gcn5 proteins, with the Snf/Swi and Srb/mediator complexes. Genetics. 1997;147:451-65 pubmed
    ..These findings suggest that SAGA has multiple activities and plays critical roles in transcription by RNA polymerase II. ..
  14. Piruat J, Aguilera A. Mutations in the yeast SRB2 general transcription factor suppress hpr1-induced recombination and show defects in DNA repair. Genetics. 1996;143:1533-42 pubmed
    ..that the hrs2-1 mutation, isolated as a suppressor of the hyperrecombination phenotype of hpr1 delta, is in the SRB2 gene, which encodes a component of the RNA polII holoenzyme...
  15. Yudkovsky N, Ranish J, Hahn S. A transcription reinitiation intermediate that is stabilized by activator. Nature. 2000;408:225-9 pubmed
    ..The scaffold is stabilized in the presence of the activator Gal4-VP16, but not Gal4-AH, suggesting a new role for some activators and Mediator in promoting high levels of transcription. ..
  16. Malagon F, Jensen T. The T body, a new cytoplasmic RNA granule in Saccharomyces cerevisiae. Mol Cell Biol. 2008;28:6022-32 pubmed publisher
    ..In contrast, the deletion of genes encoding the Mediator transcription initiation factor subunits Srb2p and Srb5p as well as the Ty1 transcriptional regulator Spt21p greatly enhances T-body formation...
  17. Esnault C, Ghavi Helm Y, Brun S, Soutourina J, Van Berkum N, Boschiero C, et al. Mediator-dependent recruitment of TFIIH modules in preinitiation complex. Mol Cell. 2008;31:337-46 pubmed publisher
    ..We conclude that the Mediator head module plays a critical role in TFIIH and TFIIE recruitment to the PIC. We identify steps in PIC formation that suggest a branched assembly pathway. ..
  18. Hausmann S, Zheng S, Costanzo M, Brost R, Garcin D, Boone C, et al. Genetic and biochemical analysis of yeast and human cap trimethylguanosine synthase: functional overlap of 2,2,7-trimethylguanosine caps, small nuclear ribonucleoprotein components, pre-mRNA splicing factors, and RNA decay pathways. J Biol Chem. 2008;283:31706-18 pubmed publisher RNA end processing and decay (Pat1, Lsm1, and Trf4) and regulation of polymerase II transcription (Rpn4, Spt3, Srb2, Soh1, Swr1, and Htz1)...
  19. Liu Z, Myers L. Med5(Nut1) and Med17(Srb4) are direct targets of mediator histone H4 tail interactions. PLoS ONE. 2012;7:e38416 pubmed publisher
    ..This analysis has identified the Med5 subunit of Mediator as a target for histone tail interactions and suggests that the previously observed effect of med5 mutations on telomeric heterochromatin and silencing is direct. ..
  20. Linder T, Rasmussen N, Samuelsen C, Chatzidaki E, Baraznenok V, Beve J, et al. Two conserved modules of Schizosaccharomyces pombe Mediator regulate distinct cellular pathways. Nucleic Acids Res. 2008;36:2489-504 pubmed publisher
    ..pombe Mediator. We report the identification of the S. pombe Med20 head subunit and the isolation of ts alleles of the core head subunit encoding med17+...
  21. Koschubs T, Lorenzen K, Baumli S, Sandström S, Heck A, Cramer P. Preparation and topology of the Mediator middle module. Nucleic Acids Res. 2010;38:3186-95 pubmed publisher
    ..The subunits, Med1 and Med10, which bridge to the Mediator tail module, bind to both Med7 and Med4. ..
  22. Lee T, Wyrick J, Koh S, Jennings E, Gadbois E, Young R. Interplay of positive and negative regulators in transcription initiation by RNA polymerase II holoenzyme. Mol Cell Biol. 1998;18:4455-62 pubmed
    ..Taken together, these results suggest that transcription initiation involves a dynamic balance between activation mediated by specific components of the holoenzyme and repression by multiple TBP-associated regulators. ..
  23. Herbig E, Warfield L, Fish L, Fishburn J, Knutson B, Moorefield B, et al. Mechanism of Mediator recruitment by tandem Gcn4 activation domains and three Gal11 activator-binding domains. Mol Cell Biol. 2010;30:2376-90 pubmed publisher
    ..Our combined results show gene-specific coactivator requirements, a surprising redundancy in activator-target interactions, and an activator-coactivator interaction mediated by multiple low-affinity protein-protein interactions. ..
  24. Liao S, Zhang J, Jeffery D, Koleske A, Thompson C, Chao D, et al. A kinase-cyclin pair in the RNA polymerase II holoenzyme. Nature. 1995;374:193-6 pubmed
    ..These results indicate that the SRB10/11 kinase is involved in CTD phosphorylation and suggest that this modification has a role in the response to transcriptional regulators in vivo. ..
  25. Koleske A, Buratowski S, Nonet M, Young R. A novel transcription factor reveals a functional link between the RNA polymerase II CTD and TFIID. Cell. 1992;69:883-94 pubmed
    ..We have investigated the function of the SRB2 gene, which was isolated as a dominant suppressor of CTD truncation mutations...
  26. Eyboulet F, Wydau Dematteis S, Eychenne T, Alibert O, Neil H, Boschiero C, et al. Mediator independently orchestrates multiple steps of preinitiation complex assembly in vivo. Nucleic Acids Res. 2015;43:9214-31 pubmed publisher
    ..This study provides an extensive genome-wide view of Mediator's role in PIC formation, suggesting that Mediator coordinates multiple steps of a PIC assembly pathway. ..
  27. Cai G, Imasaki T, Yamada K, Cardelli F, Takagi Y, Asturias F. Mediator head module structure and functional interactions. Nat Struct Mol Biol. 2010;17:273-9 pubmed publisher
    ..The Head module adopts several conformations differing in the position of a movable jaw formed by the Med18-Med20 subcomplex...
  28. Sterner D, Grant P, Roberts S, Duggan L, Belotserkovskaya R, Pacella L, et al. Functional organization of the yeast SAGA complex: distinct components involved in structural integrity, nucleosome acetylation, and TATA-binding protein interaction. Mol Cell Biol. 1999;19:86-98 pubmed
    ..Loss of either of these causes slight impairment in vivo, but loss of both is highly detrimental to growth and transcription. ..
  29. Lee Y, Min S, Gim B, Kim Y. A transcriptional mediator protein that is required for activation of many RNA polymerase II promoters and is conserved from yeast to humans. Mol Cell Biol. 1997;17:4622-32 pubmed
    ..A database search revealed the existence of MED6-related genes in humans and Caenorhabditis elegans, suggesting that the role of mediator in transcriptional activation is conserved throughout the evolution. ..
  30. Eychenne T, Novikova E, Barrault M, Alibert O, Boschiero C, Peixeiro N, et al. Functional interplay between Mediator and TFIIB in preinitiation complex assembly in relation to promoter architecture. Genes Dev. 2016;30:2119-2132 pubmed
    ..This study thus provides mechanistic insights into the coordinated function of Mediator and TFIIB in PIC assembly in different chromatin contexts. ..
  31. Qiu H, Hu C, Zhang F, Hwang G, Swanson M, Boonchird C, et al. Interdependent recruitment of SAGA and Srb mediator by transcriptional activator Gcn4p. Mol Cell Biol. 2005;25:3461-74 pubmed
    ..Thus, while Tra1p can bind directly to Gcn4p in vitro, it requires other SAGA subunits for efficient recruitment in vivo. ..
  32. Dettmann A, Jäschke Y, Triebel I, Bogs J, Schröder I, Schüller H. Mediator subunits and histone methyltransferase Set2 contribute to Ino2-dependent transcriptional activation of phospholipid biosynthesis in the yeast Saccharomyces cerevisiae. Mol Genet Genomics. 2010;283:211-21 pubmed publisher
    ..In contrast, Ino2 directly binds to the Set2 histone methyltransferase. Mapping of interaction domains revealed the importance of the SET core domain which was necessary and sufficient for binding Ino2. ..
  33. Wade P, Jaehning J. Transcriptional corepression in vitro: a Mot1p-associated form of TATA-binding protein is required for repression by Leu3p. Mol Cell Biol. 1996;16:1641-8 pubmed
    ..In addition, a mutation in the Mot1 gene leads to partial derepression of the Leu3p-dependent LEU2 promoter. These in vivo and in vitro observations define a role for Mot1p as a transcriptional corepressor. ..
  34. Miller C, Matic I, Maier K, Schwalb B, Roether S, Strasser K, et al. Mediator phosphorylation prevents stress response transcription during non-stress conditions. J Biol Chem. 2012;287:44017-26 pubmed publisher
    ..Thus dynamic and differential Mediator phosphorylation contributes to gene regulation in eukaryotic cells. ..
  35. Cheng J, Gandolfi M, Ptashne M. Activation of the Gal1 gene of yeast by pairs of 'non-classical' activators. Curr Biol. 2004;14:1675-9 pubmed
    ..The results are consistent with the finding that the classical activator Gal4, working at the GAL1 promoter, activates transcription by (at least in part) independently recruiting SAGA and Mediator. ..
  36. Shaikhibrahim Z, Rahaman H, Wittung Stafshede P, Bjorklund S. Med8, Med18, and Med20 subunits of the Mediator head domain are interdependent upon each other for folding and complex formation. Proc Natl Acad Sci U S A. 2009;106:20728-33 pubmed publisher
    We have studied folding and complex formation of the yeast Mediator head-module protein subunits Med8, Med18, and Med20. Using a combination of immunoprecipitation, far-UV circular dichroism, and fluorescence measurements on ..
  37. Peiró Chova L, Estruch F. The yeast RNA polymerase II-associated factor Iwr1p is involved in the basal and regulated transcription of specific genes. J Biol Chem. 2009;284:28958-67 pubmed publisher
  38. Natarajan K, Jackson B, Rhee E, Hinnebusch A. yTAFII61 has a general role in RNA polymerase II transcription and is required by Gcn4p to recruit the SAGA coactivator complex. Mol Cell. 1998;2:683-92 pubmed
    ..Our results provide strong evidence that recruitment of SAGA, in addition to holoenzyme, is crucial for activation by Gcn4p in vivo and that yTAFII61 plays a key role in this process. ..
  39. Peiró Chova L, Estruch F. Specific defects in different transcription complexes compensate for the requirement of the negative cofactor 2 repressor in Saccharomyces cerevisiae. Genetics. 2007;176:125-38 pubmed
  40. Drysdale C, Jackson B, McVeigh R, Klebanow E, Bai Y, Kokubo T, et al. The Gcn4p activation domain interacts specifically in vitro with RNA polymerase II holoenzyme, TFIID, and the Adap-Gcn5p coactivator complex. Mol Cell Biol. 1998;18:1711-24 pubmed
    ..of transcription factor IID (TFIID) (yeast TAFII20 [yTAFII20], yTAFII60, and yTAFII90), the holoenzyme mediator (Srb2p, Srb4p, and Srb7p), and the Adap-Gcn5p complex (Ada2p and Ada3p)...
  41. Wu X, Wilcox C, Devasahayam G, Hackett R, Ar valo Rodr guez M, Cardenas M, et al. The Ess1 prolyl isomerase is linked to chromatin remodeling complexes and the general transcription machinery. EMBO J. 2000;19:3727-38 pubmed publisher
    ..In this model, Ess1 binds and isomerizes the CTD of RNA polymerase II, thus altering its interaction with proteins required for transcription of essential cell cycle genes...
  42. Nonet M, Young R. Intragenic and extragenic suppressors of mutations in the heptapeptide repeat domain of Saccharomyces cerevisiae RNA polymerase II. Genetics. 1989;123:715-24 pubmed
    ..An extragenic suppressing mutation (SRB2-1) was isolated that strongly suppresses the conditional and auxotrophic phenotypes of CTR domain mutations...