[Frontier Leaders] Coordination of DNA Replication with Cell Division in Streptococcus pneumoniae

Frontier Leaders Seminar

Title: Coordination of DNA Replication with Cell Division in Streptococcus pneumoniae

Speaker: Jan-Willem Veening

Affiliation: University of Lausanne

Abstract:

To prevent detection by the human immune system, the opportunistic pathogen Streptococcus pneumoniae has evolved to remain small in size and only contain a single chromosome per cell. How it regulates replication with growth and division to establish this haploidy is unknown. Here, Veening will present the identification and characterisation of a unique conserved cell cycle regulator named CcrZ (Cell Cycle Regulator protein Z). We show that CcrZ is a kinase and localizes at mid-cell via a direct interaction with FtsZ. In the absence of CcrZ, a large proportion of cells are without DNA and we show that CcrZ controls the initiation of replication by regulating the activity of Dana. Together, these findings support a model in which Z-ring formation acts as a timer to trigger initiation of replication by locally increasing the CcrZ concentration at mid-cell, thereby activating origin-bound DnaA. This provides an elegant solution to ensure DNA replication is correctly timed with cell growth that initiates at the Z-ring, making sure the chromosome is only replicated once per cell cycle.

Short bio: 

Veening obtained his Ph.D. from the University of Groningen, the Netherlands, and received postdoctoral training at the Centre for Bacterial Cell Biology, Newcastle University, UK. In 2009, he established his own research and teaching group in the Groningen Biomolecular Sciences and Biotechnology Institute at the University of Groningen. In 2016, he moved to the University of Lausanne as full professor at the Department of Fundamental Microbiology. The Veening lab uses systems and synthetic biology approaches to study chromosome segregation, mechanisms of antibiotic resistance development, and noise in gene expression in the important opportunistic human pathogen Streptococcus pneumoniae. For more information, go to: https://veeninglab.com/