9 March Thesis defense Tim Hoek: “Visualizing mRNA quality control” Back to news Tim Hoek, from the group of Marvin Tanenbaum, successfully defended his thesis “Visualizing mRNA quality control: Mechanistic insights from translational dynamics” on the 9th of March. Together with his colleagues, he developed various methods with which the translation of RNA to protein can be visualized. He also studied how cells control the quality of RNA and degrade faulty RNA. At the end of his PhD, Hoek also helped develop a new Covid-19 test robot that can process up to 20.000 tests per day. Protein factories Proteins are the functional building blocks of cells. Cells make proteins by first copying DNA into an RNA molecule; this is also called transcription. Then, during a process called translation, ribosomes use the RNA molecule as a blueprint for making proteins. The ribosomes function as protein factories as it were. During the production of proteins, it is important that the correct (amounts of) proteins are present in cells. For example, muscle cells need a lot of proteins to be able to contract, whereas nerve cells do not use this type of protein as much. It is also important that faulty RNA molecules are degraded before they are translated into proteins. However, much was still unknown about the translation and quality control of RNA molecules as current techniques cannot provide detailed insight into the molecular processes. Fluorescent proteins Together with his colleagues, Hoek therefore developed various methods with which the RNA translation and quality control can be visualized. The “SunTag translation visualization system” forms the basis of these methods. The researchers place a SunTag protein in a specific gene, after which a fluorescent protein binds to the SunTag. This fluorescent protein is visible under the microscope as a green dot. The more actively the RNA is translated, the bigger the green dot. Using this technique, living cells can be filmed for up to days to observe how RNA translation proceeds over time. Hoek and his colleagues also expanded the SunTag method, making it possible to see up close how cells control the quality of RNA molecules and degrade faulty RNA. Covid-19 test robot When the lab work for his thesis was largely completed, the global corona pandemic started. Hoek used the last six months of his PhD to help develop a new Covid-19 test robot. He focused on the molecular biology behind the well-known PCR test. The large-scale collaboration with, among others, the Ministry of Health, Welfare and Sport, resulted in the development of a test robot that can process up to 20.000 tests per day. “That was a great opportunity, to contribute to the development of the test robot. I really enjoyed that,” says Hoek. Next steps Although there have certainly been stressful periods, Hoek’s PhD trajectory went relatively smoothly. Still, he is not sure whether he will further pursue a career in science. “I prefer to travel for a longer period first. To find out what the best next step is for me: a postdoc or something else. I like science, but there are also other things that interest me. Although, I have to wait until traveling is an option again of course.” Now that he completed his defense, Tim Hoek will continue his research in Tanenbaum’s lab for a few more months, after which he will take a break to think about the next step in his career.