Research Expertise and Interest
cryo-EM, biochemistry, complex biological assemblies, structure and regulation of the cytoskeleton, microtubule dynamics, human transcriptional initiation machinery, epigenetics, gene silencing, biophysics
Eva Nogales is a Professor of Biochemistry, Biophysics and Structural Biology, and a Howard Hughes Investigator. The Nogales lab is dedicated to gaining mechanistic insight into crucial molecular processes in the life of the eukaryotic cell. Their two main research themes are the dynamic self-assembly of cytoskeleton during its essential functions in cell division, and the molecular machines governing the regulation of gene expression, specially at the transcriptional level. The unifying principle in their work is the emphasis on studying macromolecular assemblies as whole units of molecular function by direct visualization of their architecture, functional states and regulatory interactions. With this overall aim in mind they use electron microscopy and image analysis, complemented with biochemical and biophysical assays, towards a molecular understanding of their systems of interest.
Microtubule Structure and Dynamics
Microtubules are essential cytoskeletal polymers involved in processes as diverse as intracellular traffic and cell division. A long-standing interest of her lab concerns the process of microtubule dynamic instability and its role in mitosis. A large number of cellular factors regulate this dynamic behavior. We have defined the structure of the microtubule at the atomic level, and the conformational changes that accompany GTP hydrolysis and lead to microtubule destabilization, Their microtubule cytoskeleton studies also emphasize the dynamic interactions of microtubule with cellular factors, specially those involved in cell division. Many such factors, by interacting with the dynamic ends of microtubules, are able to modify the behavior of these polymers and to make use of the unique structures at microtubule ends to localize in space and time, or to change microtubule dynamics.
Regulation of Gene Expression: Transcription Initiation
The regulated transcription of genes in all eukaryotes requires the assembly of a complex molecular machine around the transcription start site. Electron microscopy is ideally suited to the study large macromolecular complexes. The Nogales lab has used cryo-EM to define the structure and functional transitions of the human transcription preinitiation complex, which includes TFIID, TFIIA, TFIIB, TFIIE, TFIIF, TFIIH and RNA pol II. Their goal is now to characterize their mechanism of action in the context of chromatin, as well as their interaction activators, repressors and cofactors to generate an integrated, mechanistic model of transcriptional regulation.
Regulation of Gene Expression: Gene Silencing by PRC2
Polycomb Repressive Complex 2 (PRC2) is essential for gene silencing, establishing transcriptional repression of specific genes by tri-methylating Lysine 27 of histone H3, which ultimately lead to chromatin compaction. The NOgales lab have used cryo-EM to define the structure of PRC2 bound to two critical cofactors, and visualized the interaction of PRC2 bound to a dinucleosome. We are continuing our structural studies, complemented with activity assays, to explore the complex regulation that arises form the cross-talk between PRC2 dofferent cofactors and different chromatin state (post-translational modifications of histone tails).