Date: 26 October 2026 (Monday)
Time: 4:00 pm – 5:00 pm
Venue: Seminar Room 301, 3/F, William M.W. Mong Block, 21 Sassoon Road 
Host: Professor Yang Liu

Beginning with nucleosome structure determination, Prof. Luger has now focused on the structure and mechanism of large macromolecular assemblies involved in chromosome organization. Luger lab works towards a quantitative, mechanistic and structural description of nucleosome assembly/disassembly and investigates the function of histone chaperones, chromatin remodeling factors and histone variants. Luger lab also leads a vibrant research addressing the structure, enzymology and inhibition of Poly(ADP-ribose) polymerases, with an eye towards the design of better cancer drugs. Beyond eukaryotes, Luger lab studies histone-based chromatin organization in non-eukaryotic organisms, and this research has revolutionized our view of histones as genome-organizing entities

The timed and coordinated disruption and restoration of chromatin is a fundamental challenge for eukaryotic cells. How chromatin is restored in the wake of replication is increasingly understood. Far less is known about how chromatin is maintained in non-dividing cells, which assembles independently of DNA replication.

Human HIRA, a 1.8-megadalton complex, mediates replication-independent nucleosome assembly for histone variant H3.3, the predominant form of H3 in non-replicating cells. We show that HIRA specifically incorporates H3.3 into nucleosomes and remains engaged with the nucleosome it assembles. Cryo-EM structures reveal that HIRA forms an extended, arch-like structure that cradles the nucleosome during the final stage of assembly, making extensive contacts through its largest subunit. Our work points to an unexpected mechanism of nucleosome assembly in the cell.

Nucleosomes and histones were long thought to be unique to eukaryotes, enabling the packaging of greatly expanded genomes that arose during early eukaryogenesis. We find that histones also exist in archaea, bacteria and some viruses, offering new insight into the evolutionary origins of eukaryotic genome packaging.

All are welcome.