Professor Yukihide Tomari

Written by Dr. Anca F. Savulescu

Dr. Yukihide Tomari is a Professor at the Institute for Quantitative Biosciences (IQB) at the University of Tokyo in Japan. He received his PhD from the University of Tokyo, where he studied the reaction mechanism of the CCA-adding enzyme in Professor Takuya Ueda’s group. He then joined Prof. Phillip D. Zamore’s group as a post-doctoral fellow at the University of Massachusetts, where he studied small RNAs. According to Prof. Tomari, Prof. Zamore taught him how to enjoy doing good science. Following his post-doctoral studies, Prof. Tomari returned to Japan to start his independent research group at the University of Tokyo, studying various aspects of non-coding RNAs (ncRNAs). Prof. Tomari states that the daily lives and scientific activities of laboratory scientists are quite similar between the US and Japan. However, according to him, labs in the US feature more diversity in people’s cultural backgrounds and their ways of thinking. He adds: “This diversity greatly helped me realize what I am good (or bad) at and who I am.” Prof. Tomari’s work has been widely recognized and he is the recipient of several awards, including Human Frontiers Career Development Award, Japan Academy Medal, and Inoue Prize for Science.

According to Prof. Tomari, the ncRNA field has many technical challenges. In particular, some ncRNAs require specific “reaction platforms” or physical compartments in cells for their functions. For example, the piRNA pathway relies on perinuclear phase-separated granules, termed “nuage”, as well as the outer membrane of the mitochondria, where many factors are thought to be organized in a way that enables efficient piRNA biogenesis and transposon silencing. Many long ncRNAs also form various speckles in the nucleus. As these sub-cellular platforms tend to be lost by cell lysis and centrifugation, classical biochemistry, using regular cell lysate and soluble recombinant proteins, is, unfortunately, not generally useful. According to Prof. Tomari, “We will need to find a good strategy to recapitulate the intact reaction platforms in vitro.”

Prof. Tomari is also excited about Hero (HEat-Resistant Obscure) proteins. “Hero-hero” means flimsy, loose, or flexible in Japanese, and true to their name – these proteins are extremely disordered, hydrophilic, and highly charged. Further, they are required for both the stability and activity of Argonaute proteins, the core of RNA silencing. Hero proteins also protect many other proteins, including aggregation-prone proteins associated with neurodegenerative diseases. They are thought to act as natural PEGs, creating comfortable environments for unstable protein molecules, like Heroes. Ongoing research in Prof. Tomari’s group shows that Hero proteins have significant impacts on our understanding of the stability and functions of proteins and protein-RNA complexes in vitro and in vivo. Additionally, they may possibly have biotechnological and therapeutic potentials.

“Actively situating yourself in completely different environments will help you recognize your strengths and, ultimately, who you are in the world. Understanding what you are not so good at, is also valuable because that will help you find good collaborators to fill those needs.”

Prof. Tomari’s path in his scientific career has not always been smooth. In fact, he states that there was a time in graduate school when he deeply doubted himself. Specifically, he felt inferior to many of the other people in the lab. “I worried if I was good enough to be able to become a scientist. Although I liked doing experiments, I was not sure if I would really want to continue this career. Looking back, I realize that I was experiencing what is commonly referred to as imposter syndrome, a topic that was discussed in a Career Development Workshop I attended in RNA 2017. At the time, I felt lost and unsure of which direction to take and even attended job fairs for non-scientific careers. Meanwhile, I was enjoying playing music in jazz and funk bands, which helped me recharge, calm down and reflect on myself. Eventually, by reclaiming some personal time to ‘work on myself’, I rekindled my love for science and my passion for continuing my career as a scientist.” Further, down the line, Prof. Tomari sometimes finds that students that he comes across and discusses with, feel the same way that he had felt as a graduate student and he would like his advice and experience to be of help to them. 

In addition to science, Prof. Tomari is also involved in other scientific and professional development activities. In his lab, the team members play a game called “Are You a King? during lab meetings, using the Slack platform. In this game, the lab members are randomly divided into two teams – red and black. Each team has a king, who is randomly chosen, and whose identity is kept anonymous until the end of the game. The two kings must ask at least one question during the meeting, and the other team members ask questions as well, obscuring the identity of their own king. At the end of the game, everyone votes for whom they think the opposing team’s king might be, and they earn a point for correctly identifying the king. A small prize is given to the person with the highest score at the end of the season. According to Prof. Tomari: “This may sound a bit silly, but it really helps us to promote active discussions and to improve our skills for asking good scientific questions”. 

Prof. Tomari enjoys being a member of the RNA society, as it offers the opportunity to meet new people and learn new things in a friendly atmosphere. He especially enjoys the mentor-mentee lunch, during which, he likes absorbing energy and passion from young students. His advice to graduate students: “The world is filled with smart people with similar interests, so I think it will be helpful for you to know what you are really good at and try to make the best use of it. Things that you unconsciously take for granted may not necessarily be common for other people. Or, if you try something new, you may unexpectedly find it naturally easy and fun. These can be your unique strengths. However, it is not easy to appreciate these things in your daily life, especially if you stay in the same situation. Actively situating yourself in completely different environments will help you recognize your strengths and, ultimately, who you are in the world. Understanding what you are not so good at, is also valuable because that will help you find good collaborators to fill those needs.”

Lastly, Prof. Tomari believes that scientists are like musicians: “They both earn a living by pursuing what they love and enjoy. But, as a system, scientists are probably more stably supported than musicians. We are the lucky ones.”

Prof. Tomari’s favorite RNAs are small interfering RNAs (siRNAs), which changed his view on the function of RNAs, and he loves the 20th-anniversary special issue of the RNA journal, to which he contributed his personal reflections on his encounter with RNA ( You can follow him on Facebook (