Dyeing to see
Since 2018, the Chromatin Labeling and Imaging group has been researching special dyes to make the processes in the cell visible.
In 2018, Gražvydas Lukinavičius and his research group were just starting out. His team: a single postdoc –Jonas Bucevičius. Their plan: to label certain components of living cells to make them visible under the microscope.
The group has grown since. Instead of a two-man team the group now comprises nine scientists. “You have to find people who believe in the results. That is essential,” Lukinavičius says. “Teamwork is also very important. And you need to be tolerant and resilient.” There is no point in trying to force things. “You can try, but it still does not work. That is what I have learnt.” It takes time to build up the team as well as the laboratory and equipment.
Patience pays off
Shalini Pradhan has benefited from Lukinavičius’ patience. The PhD student joined the group in October 2020. “I am the first doctoral student Gražvydas has hired. I am like his first child,” she laughs. The biologist is now about to finish her PhD. “When I joined the group, I was so enthusiastic to join this versatile group and learn new techniques!” But there are good and bad days in research. “I think every person doing a doctorate knows this: Sometimes you get frustrated and ask yourself: ‘Why is it not working?’ Whenever I was at this point, Gražvydas was very patient and tried to motivate me. He said: ‘It is science, it takes time. It will work out all right.’”
Making the nanocosmos visible
Lukinavičius has gathered an interdisciplinary team around him: biochemists, chemists, and biologists. The group focuses on biological labeling – a technique that uses special markers and probes to modify interesting cell regions to observe them under the microscope. The scientists work at the nanometer level: They mark chromatin, a complex of DNA, RNA, and proteins that makes up chromosomes. Marking the DNA must not affect or minimally alter its behavior or structure.
The markers and probes developed by the research group are fundamental for high-resolution insights into the interior of the cell. For example, when it comes to nuclear morphology, the arrangement of components in the cell nucleus: Where the chromosomes or specific DNA sections are located in the cell nucleus plays a decisive role when cells divide, when nerve cells transmit signals but also, when cancer develops. “Nuclear morphology has been used for decades to diagnose various types of cancer,” explains Lukinavičius. “Modern super-resolution fluorescence microscopy techniques now enable researchers to image the nucleus in living cells.” If the structure of the nucleus of cancer cells, for example, is altered compared to healthy cells, this can be used to identify and target cancer cells.
Pradhan is working on labeling DNA in a living system, for example. “I inject mice with non-toxic probes that we have synthesized. I then investigate how the labeled probes distribute and how they affect different tissues.” So far, she has achieved good results. “If it works very well, it can also be used for diagnostic purposes.”
What is to come
Lukinavičius’ research goal in 2018 was to develop specific markers. “We have more or less achieved that,” he says. For example, the team succeeded to optimize fluorescent dyes in a way that they can enter living cells more easily. By combining the new dyes with 3D STED microscopy, the scientists could observe tiny structures of the cytoskeleton measuring just approximately 20 nanometers, that is, 20 millionth of a millimeter.
The work, of course, will continue. The next step will be to develop new types of markers. “It is not really a novelty in the field, but some labels are constantly used. We want to go beyond that and introduce new ones.” Building on what the team has achieved so far, the scientists want to go further. “We are always evolving, developing the lab as well. We are always looking for new researchers with different backgrounds who want to work with us.” (kf)
