ISB News

Researchers determine architecture of a macromolecular complex regulating gene expression and DNA repair

  • General transcription factor TFIIH plays central roles in gene transcription and DNA repair
  • ISB researchers and collaborators map the architecture of the TFIIH complex using powerful crosslinking-mass spectrometry (CXMS) technology and integrative modeling
  • Structural maps provide critical insights into how mutations in TFIIH subunits lead to disease phenotypes

By Jie Luo and Mark Gillespie

The expression, or transcription, of genes controls the identity and function of a cell. DNA damage caused by UV light or other carcinogens must be repaired to maintain genome integrity. The general transcription factor TFIIH plays central roles in both processes and is also important to couple gene transcription with DNA repair. Researchers at the Institute for Systems Biology, in collaboration with the University of California, San Francisco, the University of Colorado Boulder, and the Fred Hutchinson Cancer Research Center, have mapped the architecture of the multi-subunit TFIIH complex. This research, published online in Molecular Cell on Sept. 4, 2015, represents a breakthrough in understanding the structural basis for transcription and DNA repair, and provides critical insights into how disruption of the TFIIH complex can lead to cancer and other diseases.

Journal: Molecular Cell
Title: Architecture of the human and yeast general transcription and repair factor TFIIH
Authors: Jie Luo, Peter Cimermancic, Shruthi Viswanath, Christopher C. Ebmeier, Bong Kim, Vishnu Raman, Charles H. Greenberg, Riccardo Pellarin, Andrej Sali, Dylan Taatjes, Steven Hahn & Jeff Ranish
Link: read paper

TFIIH is a large multi-subunit protein complex, with flexible domains and numerous conformations, which hindered previous attempts to delineate its structure. ISB researchers Jie Luo and Jeff Ranish developed a powerful crosslinking-mass spectrometry (CXMS) approach and applied their technology to TFIIH. With CXMS, protein-protein interactions are efficiently captured using chemical crosslinkers and identified using state-of-the-art mass spectrometry. By performing their experiments on both human and yeast TFIIH, Luo and Ranish identified evolutionarily conserved crosslinks, which they used to deduce both the spatial organization and conserved protein domain interactions within the complex. This comparative CXMS strategy provided high quality spatial information to collaborators at UCSF, who subsequently used their integrative modeling platform to assemble a detailed structural model of the TFIIH complexes. From this, four new conserved “topological regions” and more than 35 conserved protein domain interactions  within TFIIH, were identified, thereby illuminating a network of interactions involved in TFIIH assembly and regulation of its activities.

Mutations in TFIIH subunits are associated with many forms of cancer and autosomal recessive disorders, such as Xeroderma Pigmentosum (XP), Tricothiodystrophy (TTD), and the combined symptoms of XP and Cockayne syndrome (XP/CS). Interestingly, most of the mutations found in patients do not directly affect the enzymatic activities of TFIIH, but rather the interactions between the enzymatic subunits and their regulatory partners. By determining the architecture of  large protein complexes, researchers can identify mechanisms explaining how mutations lead to disease phenotypes, and identify potential targets for therapeutic intervention.

 

Related Articles

  • Dr. Jeff Ranish Promoted to Professor

    We are pleased to announce the promotion of Jeff Ranish to Professor. Jeff has been a pioneer in the fields of mass spectrometry and gene regulation. His impressive history of innovation in mass spectrometry technology has produced novel protein-crosslinking approaches to identify large scale protein-protein interactions in complex mixtures. He has applied the innovations to important biological problems, resulting in notable findings such as the characterization of multiple topological and…

    Read More
  • Promotion: Dr. Jie Luo Becomes Senior Research Scientist

    Congratulations to Dr. Jie Luo, of the Ranish Lab, who has been promoted to senior research scientist. From Dr. Jeff Ranish: Jie Luo is an extremely dedicated and talented scientist. When he joined ISB in 2006 as a postdoctoral fellow, he had no experience in mass spectrometry-based proteomics. Now he is a leader in the field of structural and functional proteomics. He has conceptualized and implemented several innovative proteomics strategies…

    Read More
  • Researchers Find Key Protein Tied to Production of ‘Good’ Cholesterol

    3 Bullets: Inflammation causes cholesterol buildup and leads to cardiovascular disease, the leading cause of death in the world ISB, Seattle Biomed, and Oregon State University researchers collaborate to identify a compendium of proteins that control expression of a key regulator of cholesterol efflux Targeting cholesterol efflux to HDL is a potentially important therapeutic strategy for preventing and treating cardiovascular disease By Dr. Mark Gillespie Cells of the immune system,…

    Read More
Show More Articles