Linked Life Data

16595664

Source:http://linkedlifedata.com/resource/pubmed/id/16595664

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
22
pubmed:dateCreated
2006-5-29
pubmed:abstractText
The multisubunit Mediator is a well established transcription coactivator for gene-specific activators. However, recent studies have shown that, although not essential for basal transcription by purified RNA polymerase II (pol II) and general initiation factors, Mediator is essential for basal transcription in nuclear extracts that contain a more physiological complement of factors (Mittler, G., Kremmer, E., Timmers, H. T., and Meisterernst, M. (2001) EMBO Rep. 2, 808-813; Baek, H. J., Malik, S., Qin, J., and Roeder, R. G. (2002) Mol. Cell. Biol. 22, 2842-2852). Here, mechanistic studies with immobilized DNA templates, purified factors, and factor-depleted HeLa extracts have shown (i) that Mediator enhancement of basal transcription correlates with Mediator-dependent recruitment of pol II and general initiation factors (transcription factor (TF) IIB and TFIIE) to the promoter; (ii) that Mediator and TFIIB, which both interact with pol II, are jointly required for pol II recruitment to the promoter and that TFIIB recruitment is Mediator-dependent, whereas Mediator recruitment is TFIIB-independent; (iii) that a high level of TFIIB can bypass the Mediator requirement for basal transcription and pol II recruitment in nuclear extract, thus indicating a conditional restriction of TFIIB function and a key role of Mediator in overcoming this restriction; and (iv) that an earlier rate-limiting step involves formation of a TFIID-Mediator-promoter complex. These results support a stepwise assembly model, rather than a preformed holoenzyme model, for Mediator-dependent assembly of a basal preinitiation complex and, more important, identify a step involving TFIIB as a key site of action of Mediator.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
2
pubmed:volume
281
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
15172-81
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Human Mediator enhances basal transcription by facilitating recruitment of transcription factor IIB during preinitiation complex assembly.
pubmed:affiliation
Laboratory of Biochemistry and Molecular Biology, Rockefeller University, New York, New York 10021, USA.
pubmed:publicationType
Journal Article, In Vitro, Research Support, N.I.H., Extramural