Eukaryotic protein synthesis research group

We are interested in understanding the protein synthesis machinery in eukaryotes. The genetic information encoded in messenger RNA is translated into proteins by large ribonucleoprotein complex called ribosomes. The main research question of our studies is: How the function of eukaryotic ribosomes is determined by their structure?

To answer this question, we use a variety of methods from genetics, biochemistry and cell biology. Ongoing projects focus on ribosomal proteins (r-proteins) and the function of chemical modifications in ribosomal RNA (rRNA). Among the r-proteins, our emphasis is on eukaryotic proteins which are important for the formation of contacts between subunits of the ribosome. These contacts, called intersubunit bridges, ensure correct interaction and communication between ribosomal subunits during translation initiation and elongation steps. Of the many modifications present in rRNA, we are investigating those that are located in the functional centres of the ribosome and in the intersubunit region.

In our research we use different model systems: budding yeast (Saccharomyces cerevisiae), the Drosophila melanogaster cell line S2 and different human cell lines. Budding yeast has the advantage of rapid cell growth and the ability to efficiently rearrange the genome. We use budding yeast strains containing mutant ribosomes. These ribosomes lack the domains of some r-proteins that extend to the ribosome surface or lack some r-proteins altogether. We have also constructed budding yeast strains with ribosomes lacking some of the modifications present in rRNAs.

We use the Drosophila S2 cell line to produce heterologous proteins and then analyse how these proteins affect the protein synthesis apparatus. To modify the genome of human cells, we use CRISPR-Cas technology. The aim is to modify the genes of r-proteins so that the expressed r-proteins lack the sequences necessary to form intersubunit contacts.

We explore how mutant r-proteins or lack of rRNA modifications affect ribosome functionality. We analyse the different steps of protein synthesis, with a particular focus on initiation and elongation. Using reporter systems based on two luciferase genes, we measure the rate of elongation and fidelity of decoding. We investigate how cells with mutant ribosomes tolerate different stress conditions and how the pattern of proteins synthesised in these cells changes.

The research group is associated with the COST research cooperation network TRANSLACORE (Translational Control in Cancer European Network).

Open TRANSLACORE webpage

The research group is one of the founders of the Estonian Yeast Stock Collection “Eesti Pärmivaramu” and participates in the development of this collection.

On cover photo: Molecular machine – the ribosome - in space, guided by yeast colonies from spot-test assay.