| 词条 | Negative elongation factor |
| 释义 |
In molecular biology, NELF (negative elongation factor) is a four-subunit protein (NELF-A, NELF-B, NELF-C/NELF-D, and NELF-E) that negatively impacts transcription by RNA polymerase II (Pol II) by pausing about 20-60 nucleotides downstream from the transcription start site (TSS).[1] StructureThe NELF-A subunit is encoded by the gene WHSC2 (Wolf-Hirschhorn syndrome candidate 2). Microsequencing analysis demonstrated that NELF-B was the protein previously identified as the protein encoded by the gene COBRA1, and was shown to interact with BRCA1.[2] It is unknown whether or not NELF-C and NELF-D are peptides resulting from the same mRNA with different translation initiation sites, possibly differing only in an extra 9 amino acids for NELF-C at the N-terminus, or peptides from different mRNAs entirely. A single NELF complex consists of either NELF-C or NELF-D but not both. NELF-E is also known as RDBP.[2][3] NELF binds in a stable complex with DSIF and RNA polymerase II together, but not with either alone. P-TEFb (positive transcription elongation factor b) inhibits the effect of NELF and DSIF on Pol II elongation, via its phosphorylation of serine-2 of the C-terminal domain of Pol II, and the SPT5 subunit of DSIF, causing dissociation of NELF.[2] NELF homologues exist in some metazoans (e.g. insects and vertebrates) but have not been found in plants, yeast, or nematode (worms).[2] References1. ^{{cite journal|last1=Adelman|first1=Karen|last2=Lis|first2=John T.|title=Promoter-proximal pausing of RNA polymerase II: emerging roles in metazoans|journal=Nature Reviews Genetics|date=18 September 2012|volume=13|issue=10|pages=720–731|doi=10.1038/nrg3293|pmid=22986266|url=http://www.nature.com/nrg/journal/v13/n10/full/nrg3293.html|accessdate=18 December 2014|pmc=3552498}} {{protein-stub}}2. ^1 2 3 {{cite journal|last1=Narita|first1=Takashi|last2=Yamaguchi|first2=Yuki|last3=Yano|first3=Keiichi|last4=Sugimoto|first4=Seiji|last5=Chanarat|first5=Sittinan|last6=Wada|first6=Tadashi|last7=Kim|first7=Dong-ki|last8=Hasegawa|first8=Jun|last9=Omori|first9=Masashi|last10=Inukai|first10=Naoto|last11=Endoh|first11=Masaki|last12=Yamada|first12=Tomoko|last13=Handa|first13=Hiroshi|title=Human Transcription Elongation Factor NELF: Identification of Novel Subunits and Reconstitution of the Functionally Active Complex|journal=Molecular and Cellular Biology|date=15 March 2003|volume=23|issue=6|pages=1863–1873|doi=10.1128/MCB.23.6.1863-1873.2003|url=http://mcb.asm.org/content/23/6/1863|accessdate=18 December 2014|pmid=12612062|pmc=149481}} 3. ^{{cite journal|last1=Yamaguchi|first1=Yuki|last2=Takagi|first2=Toshiyuki|last3=Wada|first3=Tadashi|last4=Yano|first4=Keiichi|last5=Furuya|first5=Akiko|last6=Sugimoto|first6=Seiji|last7=Hasegawa|first7=Jun|last8=Handa|first8=Hiroshi|title=NELF, a Multisubunit Complex Containing RD, Cooperates with DSIF to Repress RNA Polymerase II Elongation|journal=Cell|date=April 1999|volume=97|issue=1|pages=41–51|doi=10.1016/S0092-8674(00)80713-8|url=http://www.sciencedirect.com/science/article/pii/S0092867400807138|accessdate=18 December 2014|pmid=10199401}} 3 : Protein complexes|Transcription factors|Negative concepts |
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