Biology:Selective factor 1
Selective factor 1 (also known as SL1) is a transcription factor that binds to the promoter of genes and recruits a preinitiation complex to which RNA polymerase I will bind to and begin the transcription of ribosomal RNA (rRNA).[1][2]
Discovery
SL1 was discovered by Robert Tjian and his colleagues in 1985 when they separated a HeLa cell extract into two functional fractions.[3] One factor has RNA polymerase I activity, but no ability to initiate accurate transcription of a human rRNA template. This transcription factor, SL1, showed species specificity.[4] That is, it could distinguish between the human and mouse rRNA promoter,[5] and added increasing amount of human template at the expense of the mice template.[6] Tijian and coworkers went on to show that by footprinting a partially purified polymerase 1 preparation could bind to the human rRNA promoter. In particular it causes a footprint over a region of the UCE called A site.[7] This binding is not due to polymerase I itself but to a transcription factor called upstream binding factor, UBF.
Function
SLI functions in assembling the transcription preinitiation complex. It is also a major determinant of species-specificity in ribosomal RNA gene transcription. Research suggests that UBF and SL1 act synergistically to stimulate transcription. Recent investigation also suggests that SL1 is a target for cancer therapy.[8]
Structure
SL1 is composed of the TATA-binding protein and three TAF (TATA box-binding protein-associated factor) subunits (TAF1A, TAF1B, and TAF1C).[9] It is therefore possible to inhibit SL1 activity with anti-TBP antibodies.
See also
References
- ↑ "Recruitment of TATA-binding protein-TAFI complex SL1 to the human ribosomal DNA promoter is mediated by the carboxy-terminal activation domain of upstream binding factor (UBF) and is regulated by UBF phosphorylation". Molecular and Cellular Biology 19 (4): 2872–9. 1999. doi:10.1128/MCB.19.4.2872. PMID 10082553.
- ↑ Lewin's Genes XI. https://books.google.com/books?id=yXFfPkLq4yEC&pg=PA555. Retrieved 2014-08-10.
- ↑ "Diversified transcription initiation complexes expand promoter selectivity and tissue-specific gene expression". Genes & Development 17 (11): 1309–20. 2003. doi:10.1101/gad.1099903. PMID 12782648.
- ↑ "The species-specific RNA polymerase I transcription factor SL-1 binds to upstream binding factor". Molecular and Cellular Biology 16 (2): 557–63. 1996. doi:10.1128/MCB.16.2.557. PMID 8552083.
- ↑ The Nucleolus. 2011-09-15. https://books.google.com/books?id=jnTEbintTj0C&pg=PA110. Retrieved 2014-08-10.
- ↑ "Purification and characterization of a transcription factor that confers promoter specificity to human RNA polymerase I". Molecular and Cellular Biology 5 (6): 1358–69. 1985. doi:10.1128/MCB.5.6.1358. PMID 3929071.
- ↑ "Patent US5637686 - Tata-binding protein associated factor, nucleic acids - Google Patents". https://www.google.com/patents/US5637686. Retrieved 2014-08-10.
- ↑ "The basal transcription machinery as a target for cancer therapy". Cancer Cell International 14 (1): 18. 2014. doi:10.1186/1475-2867-14-18. PMID 24576043.
- ↑ "TBP-TAF complex SL1 directs RNA polymerase I pre-initiation complex formation and stabilizes upstream binding factor at the rDNA promoter". The Journal of Biological Chemistry 280 (33): 29551–8. 2005. doi:10.1074/jbc.M501595200. PMID 15970593.
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