Structural dissection of an interaction between transcription initiation and termination factors implicated in promoter-terminator cross-talk

Matthew Bratkowski, Ilona Christy Unarta, Lizhe Zhu, Murtada Shubbar, Xuhui Huang, Xin Liu

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Functional cross-talk between the promoter and terminator of a gene has long been noted. Promoters and terminators are juxtaposed to form gene loops in several organisms, and gene looping is thought to be involved in transcriptional regulation. The general transcription factor IIB (TFIIB) and the C-terminal domain phosphatase Ssu72, essential factors of the transcription preinitiation complex and the mRNA processing and polyadenylation complex, respectively, are important for gene loop formation. TFIIB and Ssu72 interact both genetically and physically, but the molecular basis of this interaction is not known. Here we present a crystal structure of the core domain of TFIIB in two new conformations that differ in the relative distance and orientation of the two cyclin-like domains. The observed extraordinary conformational plasticity may underlie the binding of TFIIB to multiple transcription factors and promoter DNAs that occurs in distinct stages of transcription, including initiation, reinitiation, and gene looping. We mapped the binding interface of the TFIIB-Ssu72 complex using a series of systematic, structure-guided in vitro binding and site-specific photocross-linking assays. Our results indicate that Ssu72 competes with acidic activators for TFIIB binding and that Ssu72 disrupts an intramolecular TFIIB complex known to impede transcription initiation. We also show that the TFIIB-binding site on Ssu72 overlaps with the binding site of symplekin, a component of the mRNA processing and polyadenylation complex. We propose a hand-off model in which Ssu72 mediates a conformational transition in TFIIB, accounting for the role of Ssu72 in transcription reinitiation, gene looping, and promoter-terminator cross-talk.

Original languageEnglish (US)
Pages (from-to)1651-1665
Number of pages15
JournalJournal of Biological Chemistry
Volume293
Issue number5
DOIs
StatePublished - Jan 1 2018

Fingerprint

Transcription Factor TFIIB
Dissection
Peptide Initiation Factors
Transcription
Genes
Polyadenylation
Binding Sites
Transcription Factors
General Transcription Factors
Messenger RNA
Cyclins
Processing
Phosphoric Monoester Hydrolases
Crystal orientation
Plasticity
Conformations
Assays
Hand
Crystal structure

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this

Structural dissection of an interaction between transcription initiation and termination factors implicated in promoter-terminator cross-talk. / Bratkowski, Matthew; Unarta, Ilona Christy; Zhu, Lizhe; Shubbar, Murtada; Huang, Xuhui; Liu, Xin.

In: Journal of Biological Chemistry, Vol. 293, No. 5, 01.01.2018, p. 1651-1665.

Research output: Contribution to journalArticle

Bratkowski, Matthew ; Unarta, Ilona Christy ; Zhu, Lizhe ; Shubbar, Murtada ; Huang, Xuhui ; Liu, Xin. / Structural dissection of an interaction between transcription initiation and termination factors implicated in promoter-terminator cross-talk. In: Journal of Biological Chemistry. 2018 ; Vol. 293, No. 5. pp. 1651-1665.
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