Alessandro runs the Macromolecular Machines lab at the Crick, where his team study how cells begin to replicate their DNA, an essential process for life. If this goes wrong, cells can copy DNA more than once per cell cycle, which leads to chromosome instability, a hallmark of cancer.

Alessandro uses high-powered microscopes to visualise molecular machines, formed of multiple proteins which unravel and copy DNA.

While the focus of the lab to date has been studying these machines in yeast cells, in this new study, his team will also explore the complexity of human and animal DNA replication.

Collaborating with the Crick’s Chromosome Replication lab, led by John Diffley, the research team will now study human replication machines in a test tube, by imaging each step in the DNA copying process.

The researchers will use electron microscopy to reveal the structure of these molecular machines, the chemical reactions they are involved in, and when and where these reactions take place.

Alessandro and team will also take advantage of a cutting-edge imaging technology called cryo-FIB combined with another technique called cryo-electron tomography.

They will use these tools to cut thin slices of replicating frog nuclei and image the proteins in their native state rather than in a test tube.

The images will then be used to generate a 3D structure, which will allow the researchers to see where the molecular machines are, when they become activated, and how they interact.

The cryo-FIB images will be combined with traditional fluorescent microscopy, to label proteins and DNA in different colours, and then machine learning techniques will be applied to help analyse the vast amount of data.

Alessandro said: 

We are yet to recreate DNA replication using purified human proteins in the lab, possibly because we don’t know all the factors undertaking this fundamental task, and where and when they play a role.

We’re excited to embark on this journey into human DNA replication, and also use new technology to visualise exactly what’s happening in a fertilised frog egg nucleus as it first replicates its genetic information at the start of life. We’re hoping to answer some fundamental questions but will likely pick up some of our own throughout the project!

Wellcome Discovery Awards provide funding for established researchers and teams who want to pursue bold and creative research ideas to deliver significant shifts in understanding related to human life, health and wellbeing.

Alessandro’s study will begin in September 2025.