The speed at which a cell produces proteins is a decisive factor in determining whether it divides, specializes or retains its stem cell properties. A team of researchers led by Professor Stefan H. Stricker, professor of epigenetic engineering at LMU's Biomedical Center and research group leader at Helmholtz Munich, has worked with international partners to demonstrate directly for the first time that the amount of ribosomal RNA (rRNA) directly regulates these processes. Their results were published in the journal Science.

New method makes it possible to control ribosomal RNA in a targeted manner
It has been established for some time that the amount of ribosomal RNA differs among different types of cells and is altered in a number of diseases. But it remained unclear whether these specific characteristics are the cause or merely the result of biological processes.

With the newly developed CRISPR-based method TAPIR (Targeted Activation of Protein Translation), researchers now have access to a tool that can boost the activity of ribosomal genes and, as a result, influence a cell's protein production. "Our new study shows that targeted activation of rRNA production significantly increases protein synthesis," explains Stricker, lead author of the publication.

New perspectives for rare diseases and cancer
The results could be particularly relevant for diseases in which ribosome function is disrupted. These include ribosomopathies such as Treacher-Collins syndrome, a rare congenital disease that causes facial malformations. In a mouse model, the researchers partially compensated for disease-related alterations by stimulating rRNA production in a targeted way.

In addition, the research team observed that similar mechanisms also play a role in pancreatic cancer. Tumor cells seem to use increased rRNA production to maintain their rapid growth. In the mouse model for pancreatic cancer, TAPIR was able to increase rRNA production and promote the growth of the cancer cells. This shows that increased rRNA production has a causal effect in contributing to tumor growth and is not just a side effect.