Lemmens group

The recipe for life is encoded in DNA, a complex chain-like molecule built from four different types of nucleotides: A, T, C or G. The correct order of the three billion A’s, T’s, C’s and G’s of the human genome is critical, as a single mistake can be lethal or cause serious diseases such as cancer. We are interested in how human cells maintain, copy and propagate DNA.

A picture of the members in Lemmens Group at Skansen, Stockholm

Human life starts as a single cell that divides numerous times to create an entire human body consisting of trillions of cells. To maintain genome stability, cells need to faithfully replicate their DNA before dividing. A key feature of cancer cells is their forced proliferation, which causes a hasty uncontrolled start of DNA replication. To date, however, little is known about the mechanisms that control the start of DNA replication in human cells, hampering the design of better, selective cancer therapies. Studying essential, dynamic processes such as DNA replication requires conditional, time-resolved genetics. The Lemmens group develops and combines innovative protein depletion methods with cutting-edge imaging techniques to study how, when and where DNA replication starts. In parallel, we use various CRISPR-based technologies to discover new factors driving cell proliferation and cancer drug resistance. 

Research projects

We develop innovative approaches to study DNA replication with high precision in both time and space. To determine the mechanism and kinetics of human DNA replication we run various projects, ranging from targeted imaging approaches to unbiased genetic screens.

We currently focus on three projects:

  1. To study dynamic processes in human cells at single-cell resolution, our team develops rapid protein depletion methods and time-resolved analysis pipelines.
  2. To define where these processes take place in the cell, we develop cutting-edge imaging approaches, including live-cell, high-content, super resolution and/or expansion microscopy.
  3. Many of our projects involve CRISPR technologies, including gene knockouts, reporter knock-ins and gene editing approaches. We also use pooled CRISPR screens to study how human cells become resistant to cancer drugs and discover new factors controlling genome maintenance or DNA replication.

Interested in joining our team? Please feel free to email Bennie Lemmens.


Understanding human biology and finding innovative cancer cures is a global team effort. We thus aim to collaborate with scientists around the world and currently join forces with i.a.:

  • Dr. Thanos Halazonetis (University of Geneva, Switzerland)
  • Dr. Hans Blom (Advanced Light microscopy Facility; KTH, Sweden) 
  • Dr. Mirek Dundr (Rosalind Franklin University, USA)
  • Dr. Alexander van Oudenaarden (Hubrecht Institute, Netherlands)
  • Dr. Bernard Schmierer (Genome Engineering Facility; KI, Sweden)
  • Dr. Jiri Bartek (KI and Danish Cancer Society; Sweden and Denmark)  



Selected publications


We are grateful for support from:

  • The Mark Foundation for Cancer Research (US)
  • Swedish Research Council (VR)
  • Cancer Research KI
  • Swedish Cancer Foundation
  • Jeanssons foundation
  • Karolinska Institutet faculty support
  • Åke Wiberg foundation


  • Abid Hussain Sayyid, research assistant, 2021-2023
  • Konstantinos Danias, master student, 2023
  • Joana Costa, master student, 2022-2023
  • Sophie Boersma, master student, 2022
  • Gábor Merényi, research assistant, 2019-2021
  • Fenne Van Dongen, master student, 2019