Reactome | Recruitment of Acetylated SL1 to phosUBF-1:rDNA Promoter

Recruitment of Acetylated SL1 to phosUBF-1:rDNA Promoter

Stable Identifier

R-HSA-73739

Type

Reaction [binding]

Species

Homo sapiens

Compartment

nucleolus

ReviewStatus

5/5

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Recruitment of Acetylated SL1 to phosUBF-1:rDNA Promoter

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Knockdown of CSB reduces recruitment of SL1 and RNA Polymerase I to active rRNA genes. Human SL1 does not bind to DNA itself, rather it is recruited to the rDNA promoter through a physical interaction with UBF-1. Phosphorylation of UBF-1 within the carboxy-terminal region is required for SL1 binding. SL1 consists of TATA-binding protein (TBP) and three associated factors (TAFIs). SL1 has no sequence-specific DNA binding activity its recruitment to the promoter being mediated by specific interactions with UBF. Once bound the SL1 complex makes direct contact with the DNA promoter and guides promoter-specific initiation.

Studies to identify the mechanistic relationship between SL1 and UBF-1 have indicated that the interaction between UBF-1 and SL1 is regulated by tumor suppressor proteins such as Rb and P53, although it has also been proposed that Rb prevents UBF-1 from binding to DNA itself.

Literature References

PubMed ID	Title	Journal	Year
7491500	Coactivator and promoter-selective properties of RNA polymerase I TAFs. Beckmann, H, Tjian, R, O'Brien, T, Chen, JL	Science	1996
10082553	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. Tuan, JC, Comai, L, Zhai, W	Mol Cell Biol	1999
10913176	Repression of RNA polymerase I transcription by the tumor suppressor p53. Comai, L, Zhai, W	Mol Cell Biol	2000