Daniel Schümperli looks back on 40 years of RNA biology and gives insights into his career as a Professorin the field of RNA: He talks about the fascination of the breaks in the central dogma, the importance of teachers and role models, the Swiss RNA community, and the impact of science communication among peers and beyond.

Were you interested in Science as a young person?

During my childhood I liked to read adventure stories, especially ones about explorations in foreign countries. However my interest in science was mainly stimulated by a primary school teacher. I was about 10 years old when this teacher took over our class. He was so much interested in biology that he kept beetles and fish in the classroom and organized an exhibition of mushrooms, which we had collected in the forest. Infected by his enthusiasm for nature, I kept an aquarium and raised various caterpillars at home.

Initially you were trained as a veterinarian. What made you decide to transition to research in biology?

I was interested in animals and nature and initially thought of studying zoology. But then the veterinarian who treated our dog influenced me to go to vet school. Eventually, what made me move into experimental biology were two professors I had during my veterinary studies. In the first year, we had zoology courses with Ernst Hadorn, one of the pioneers of developmental biology in Switzerland. He gave excellent lectures on genetics and developmental biology that fascinated me. Maybe an even more important influence was a very young lecturer by the name of Roland von Fellenberg, who was teaching us biochemistry and immunology. What most stimulated my interest was a lecture about the recent discovery of retroviruses and reverse transcriptase. Being able to reverse the flow of genetic information seemed so interesting that I asked to do a practicum in the biochemistry lab during the summer break. Soon afterwards this activity turned into a veterinary thesis, which I completed almost simultaneously with my final exams in veterinary medicine. By then it was clear to me that I wanted to work in experimental biology, to look at genes and DNA, DNA replication or something in this direction.

”By then it was clear to me that I wanted to work in experimental biology …”

And then you went on to study RNA processing. Why did you choose to work on RNA?

I was interested in molecular biology, and RNA is part of it. After three years in a veterinary virology institute, I found an excellent postdoctoral position at the National Institutes of Health in Bethesda Maryland with an excellent molecular biologist, Marty Rosenberg. I took over a project to develop a readout system for promoters and terminators in mammalian cells. I made reporter constructs, which was quite something new. Later I got a position in Zürich as an Oberassistent of Max Birnstiel. One of the topics in the Birnstiel lab were histone genes, and I thought I would use my system to study promoters and terminators of histone genes. However, it turned out that the promoters were already very well studied by Birnstiel’s students and postdocs. So I de- cided to look at 3’ end formation. Together with a PhD student in the lab we could show that this 3’ end, which looked like a bacteri- al terminator, was actually not a terminator but a 3’ end processing site. This was when RNA processing came into the story. I had already been fascinated by RNA processing for several years - the discovery of splicing, of capping and polyadenylation, the first in vitro systems. I had read about all of that, but now, all of a sudden, I was in the middle of it. And then with my first PhD student we started to look at the cell cycle regulation of histone genes and again discovered that 3’ end formation was important for this regulation. So that’s how we got into the RNA field and followed up this lead.

And when did the U7 snRNP come into play?

That was early in the Birnstiel lab. As I said before, there were students looking at histone promoters. And there was this one student looking at 3’ end formation with whom I could show that this was a processing and not a termination event. Another person in the lab was fractionating sea urchin extracts to trace down an activity that complemented the deficient 3’ end formation of a sea urchin histone gene in the heterologous Xenopus oocyte system. It was initially thought that the active principle would be a protein. But then, soon after people in the lab tried to clone a cDNA for it, they discovered that polyadenylated RNAs couldn’t do the job but a non-polyadenylated short RNA did rescue the 3’ end formation. That’s what led to the discovery of U7 snRNA. We could show that it is involved in this processing reaction. A few years later, when I was actually studying the cell cycle regulation of the histone genes, one of my own PhD students and myself started to search for the mammalian U7 RNA. We were able to determine its sequence and publish it almost simultaneously with two other labs which were on the same track. After that, we started to study the U7 snRNA in more detail in the mammalian system.

Initially, the U7 snRNP was central in your studies on histone pre-mRNA 3’ end process- ing. Later on, you developed and used it as an antisense tool to correct aberrant splicing in beta-Thalassemia, Spinal Muscular Atrophy (SMA) and later also Erythropietic Protoporphyria (EPP). How did the idea come up to use a modified version of the U7 snRNP as a splicing modulator?

That was an interesting story. I was already in Bern, and we had just characterized the assembly of the U7 snRNP. We had found that the Sm binding site, a sequence in the RNA that recruits proteins and that is important for making this ribonucleoprotein particle and importing it into the cell nucleus, also determined the abundance of the U7 snRNA. It was not a very efficient assembly, and we could show that, if we changed the sequence of this Sm binding site into a sequence resembling the Sm binding sites of the major snRNPs involved in splicing, then we could boost the assembly. However we produced a U7 snRNA that was no longer functional in histone RNA processing. After publishing these findings, I went to one of the RNA meetings in the US and, after the meeting, flew to North Carolina to visit my competitor Bill Marzluff. He invited me for dinner and brought along a colleague, Ryszard Kole. Ryszard told me about work he was doing with antisense oligonucleotides to correct splicing. After the dinner, I returned to my hotel room and had the idea that this U7 snRNP, which was no longer functional in histone RNA processing, could be an ideal tool to express antisense sequences in the cell nucleus. The next morning I was scheduled to have a scientific discussion with Ryszard Kole, and I told him: “well I think I have a RNA that could do exactly what your oligonucleotides are doing”. We decided to start a joint project. I sent a new PhD student to North Carolina to learn the necessary techniques in Ryszard’s lab. Later I also did a sabbatical there, and we got this project going. It was really the two different observations coming together at this dinner table that had generated a new project, a new idea.

Over 20 years have passed since you did the first experiments with the U7 snRNP as a splicing modulator. Where does the research stand today?

It has been used by a number of people, including us of course. Usually it’s been suc- cessful in cell culture but it has not been applied a lot in animal models or in patients. There are a few success stories in animal models. A group in France has done successful studies on mouse and dog models for Duchenne Muscular Dystrophy (DMD). We on the other hand, have had some success recently with a mouse model for SMA, where we can show that the mice, which otherwise die within 1 or 2 weeks after birth, survive for a long time and have very moderate SMA symptoms. Otherwise, I am not aware that it has been used a lot in vivo, be it in animal models or in human beings. I think one of the problems is that industry is shying away from gene therapy. There have been unwanted side effects in some gene therapy trials. Insertional mutagenesis may lead to cancer, and in one case, where adenovirus vectors were used, inflammations occurred which caused the death of a patient. On the other hand, certain gene therapies seem to be successful and start to being used. But the field has been very slow. In part, this is due to a resistance or resilience of the industry to get into the field.

Do you see a way to overcome this resistance?

It is difficult to predict. Any success in the field will influence the attitude that people have. If one of these therapies is successful, then hopefully the industry will get into it. A gene therapy is usually a relatively severe intervention depending on what the target tissue is. I can also understand from the point of view of the patients or regulatory authorities that it might be preferable to use small molecule drugs or antisense oligonucleotides. There are a few success stories with antisense oligonucleotides that have gone to the clinic and there are also promising candidate drugs that can modulate splicing. However it is not yet clear what kind of side effects these drugs will have. What works and what will eventually become state of the art in terms of correcting splicing diseases will very much depend on the success of these individual stories.

“… the connectedness of the field is growing and developing, and this is a strong bonus for the future.”

How did you experience the development in the RNA field throughout your career?

I think it was great. It was just very thrill- ing to see all these developments. I told you that initially what more or less got me into the field was this mention of reverse transcription. The genetic code and the discovery of translation were before my time and were very interesting. But then came all these breaks of the central dogma: the reverse transcriptase, RNA processing, RNA editing – all this happened during my lifetime, and I was part of it. Almost each new congress came with a new exciting discovery. Later there was RNA interference, microRNAs and all the non-coding RNAs. The field has kept on providing surprises and interesting things that nobody ever believed possible. I think it is a great field.

Throughout your career as a group leader, you trained over 50 scientists as diploma and master students, PhD students, and postdocs. Many of them are today independent group leaders in Switzerland and abroad. What is your recipe as a successful mentor and what would you advise junior scientists to succeed in their academic careers?

My role model as a mentor was Marty Rosenberg, my supervisor during my post- doc in the US. This was a lab that functioned more or less without pressure. It was completely controlled by excitement, enthusiasm, a very collegial atmosphere, doing things together and finding that research is fun and exciting. I tried to copy this for my own group. Whether I succeeded is difficult to say. If you can provide an atmosphere where people can experience this enthusiasm and share

it with others, I think that is the best you can do. People should find out what excites them, what they are really interested in, and then try to follow that lead. The best you can do is to do that for which you are highly motivated. Then you have the best chance to become good in your field and to succeed. I know that quite a number of people have suggested the same. I remember when I started my own studies that one of the older professors in Zürich had an introductory lecture and was saying exactly the same: “don’t just look at what the job market will be or where you could find chances of going, but try to find out what really interests you and then move forward”.

In the NCCR RNA & Disease you were very committed as the leader of the “RNA metabolism” work package, as the delegate for communication, and as member of the steering committee. How do you think the NCCR influences the Swiss RNA community and where do you see the potential of this NCCR in the future?

The Swiss RNA community was already quite well connected before the NCCR. We had the annual Swiss RNA Workshop. Also, going to the same meetings, meeting people abroad at RNA meetings – for example those of the international RNA Society – was always a good way to connect the field. What the network has brought in addition are all these common activities like summer schools, meetings between the groups, between the PIs, but, most importantly, between students and postdocs. I can really feel in those meetings that the connectedness of the field is growing and developing, and this is a strong bonus for the future. What is a bit more difficult to predict, is the influence it will have in the broader sense: like connecting to the medical community or the private sector. Those are certainly fields where networking is much more difficult to establish but will be important. And it will be a challenge for the network to succeed in generating such connections.

You put significant effort into public outreach. How important is it to communicate the science to the public and medical community?

For me, it started out of a personal neces- sity. When I returned from my postdoctoral stay in the US, I started as an Obersassistent in Max Birnstiel’s lab, in one of the best labs in Europe or in the world. I came back to Switzerland, and there was such a negative attitude towards molecular biology, towards cloning and gene technology. Many of the people whom I interacted with, whom I loved or liked were very negative. This put me in a difficult position. I had to find ways of justi- fying what I was doing, and I was struggling with this. I realized that, as a scientist, one could not just pretend that these problems didn’t exist but that one had to do something about it. Later, when I had become a professor in Bern, I was asked to do something for the broader community. While others may have served on the scientific board of the Swiss National Science Foundation or have done something within science, I was asked by the Swiss Academy of Sciences to get into science communication. At this time, they set up a forum on gene technology, “Forum Genforschung”, which was more or less a reaction to criticism in the society and to a people’s initiative, the “Genschutzinitiative”, that would have forbidden quite a number of activities. I worked in the board of this forum for quite a while and later became its chairman. We tried to establish a dialogue with stakeholders in the field, such as consumer organizations, animal protection people, people in the agricultural community and politicians. I think that was really important work. Personally, I was at that time a member of the social democrat party. I joined a committee that was counseling the party’s parliament members on all kinds of issues related to education and science. Of course, gene technology was one of the hot topics there. I tried to communicate to the people what I was thinking of the field and could to some extent act as a mediator. I saw that there were lots of fears and antagonisms against this area of research. In the long run, if we want to use the money of the taxpayers, we as scientists need to provide something that is of interest to the community as a whole and we need to justify what we are doing. It is also important in terms of culture. The public knowledge of science is probably more or less at the level of the 1930s, 1940s – the time of the discovery of antibiotics. Many of the new things that have happened since the 2nd world war have not gone into general culture. One needs to do something to communicate these things and to help the society to integrate the new knowledge.