How single-celled life becomes multicellular

Sixty per cent of our genes are regulated by micro-RNA, a type of non-coding RNA molecule that is not converted into proteins. One hypothesis is that these are involved in the transition from single-celled to multicellular life.

– In 2007, we were among the first to show that micro-RNA is not only found in animals and plants, says Fredrik Söderbom, professor at the Department of Cell and Molecular Biology, who researches gene regulation with a focus on non-coding RNA.

– We made the discovery together with Victor Ambros, who was awarded the Nobel Prize in Physiology or Medicine in 2024.

Fredrik Söderbom studies organisms that are considered single-celled but can develop into multicellular organisms. He uses slime moulds as model organisms.

– Unfortunately, that's what they're called, but they're not fungi, they're amoebas. Evolutionarily, they are as little like fungi as they are like animals or plants. However, they resemble fungi and are often seen in nature.

When these so-called social amoebas are exposed to starvation, they send signals to each other and join together to form a multicellular fruiting body with spores and a stalk. This is a form of multicellularity that has arisen several times during evolution. The advantage of studying this type of amoeba is that you can look at single-celled and multicellular life in the same organism and follow the different stages of development in a way that would be more difficult with animals, for example.

– What we want to know is what drives the transition from single-celled to multicellular life, whether it is non-coding RNA that controls it. We now believe that we have found a type of RNA that is involved, says Fredrik Söderbom, who emphasises that basic research such as this is a prerequisite for applied research.

– That is why it is important that research projects from both sides are included in the area of strength Evolution and biodiversity in a changing world.

The knowledge gained from studying model organisms can ultimately contribute to the development of better medicines for humans. Diseases such as cancer are linked to non-coding RNA. We can also gain a better understanding of biological diversity by studying these molecules.

– We expect our studies to lead to knowledge about how non-coding RNA molecules can regulate complex processes such as the development of an organism, and to provide insight into how they can drive evolution from a simple cell to a multicellular organism, says Fredrik Söderbom.

Sigrid Asker