On December 4, 2017, Professor Bruce Stillman, FRS and a member of US National Academy of Sciences, from Cold Spring Harbor Laboratory visited IBP to gave a Bei Shizhang lecture entitled “Inheritance of the Genome of Eukaryotes: ORC and the Control of Cell Division”. Researchers and graduate students from both inside and outside of IBP attended in this seminar.

Professor Stillman is a renowned expert in DNA replication and cancer biology. He is a senior member at Cold Spring Harbor Laboratory, and has been the Director since 1994. He also served as the Director of the NCI-designated Cancer Center for 25 years from 1992 to 2016. Working with yeast and human cells, Professor Stillman and colleagues have identified many of the cellular proteins that function at the DNA and chromosome replication. One of his major accomplishments was the discovery of the Origin Recognition Complex (ORC)

ORC is made up of six protein subunits that binds to cellular origins of DNA replication and coordinates the initiating a complete cycle of DNA replication. ORC also binds with other initiation proteins and together form the pre-replication complex (pre-RC). Professor Stillman introduced the Cryo-EM structures of pre-RC, and the formation of the OCCM complex by the recruitment of the Cdt1-Mcm2-7 heptamer through the ORC-Cdc6 helicase loader complex during initiation of DNA replication. Consequently, the double hexamer recruits Cdc45 and GINS to form two active and separate CMG helicase, which encircles the leading strand while excluding the lagging strand. Professor Stillman also introduced the cell cycle function of pre-RC proteins. Among them, ORC1 coordinates with cylin A to inhibit Cyclin E-dependent centriole and centrosome re-duplication, and its localization to centrosomes.

Prof. Stillman’s talk was received with great enthusiasm. Many researchers and students participated in active exchanges with Professor Stillman after his talk.

Prof. Stillman was giving a Bei Shizhang lecture

Prof. Stillman and Prof. Ruiming Xu

The audience