RNA is often represented as linear and single-stranded. But this macromolecule can turn into more complex shapes. For example, RNA structures such as RNA G-quadruplexes have been observed in laboratory conditions formed in a physiological concentration of potassium.
Therefore, it has been suggested that these highly stable secondary structures have significant biological relevance and must exist in nature. Till now, there is a lack of direct evidence for RNA G-quadruplex formation in living eukaryotic cells. Therefore, it is unclear whether any purported functions are associated with the specific sequence content or an RNA G-quadruplex structure.
Now, scientists at the John Innes Center have resolved a longstanding biological debate by revealing the existence and function of complex RNA structures in plants. This is the first direct evidence of RNA G-quadruplex formation in living eukaryotic cells.
Scientists investigated genetic regions rich in guanine, one of the four main nucleobases found in DNA and RNA. These regions have in lab conditions shown the potential to form RNA G-quadruplex motifs.
They used chemical structure profiling to determine multiple RNA G-quadruplex structures strongly folded in the model species Arabidopsis and rice.
Subsequent genetic and biochemical analysis showed that RNA G-quadruplex folding can regulate the fundamental biological process of translation from RNA to proteins and has a function in modulating plant growth.
Corresponding author Dr. Yiliang Ding says: “Our work has tried to understand the structure of RNA inside the cell over the past five years. For the first time, we have answered the longstanding question about whether RNA G-quadruplex structures exist in living eukaryotic cells. Given that we have revealed the presence of a large number of RNA G-quadruplex structures in plants, the next step is to unravel their regulatory roles in plant growth, development, and stress response.”
- Xiaofei Yang et al. RNA G-quadruplex structures exist and function in vivo in plants, Genome Biology (2020). DOI: 10.1186/s13059-020-02142-9