Dr Bungo Akiyoshi

Evolutionary cell biology of chromosome segregation

How do cells get the right number of chromosomes during cell division? This fundamental question in biology has been studied for more than a century, but there are still lots of mysteries to be solved. This process, called chromosome segregation, is driven by two key players in eukaryotes: microtubules and kinetochores. Microtubules are polymers that dynamically grow and shrink by incorporating or dissociating tubulin subunits at the tips. The kinetochore is a macromolecular protein complex that assembles onto the centromere of each chromosome and mediates the interaction with microtubules to enable chromosome movement. Although microtubules are highly conserved, components of kinetochores are highly variable among eukaryotes. The most divergent kinetochores are found in a group of unicellular flagellated eukaryotes, called kinetoplastids, which are evolutionarily-distant from conventional model eukaryotes. My group is studying unconventional kinetoplastid kinetochores to better understand the mechanism of chromosome segregation.

Our focus is on 20 kinetoplastid kinetochore proteins (KKT1-20) that we recently identified in Trypanosoma brucei, a kinetoplastid parasite that causes human African trypanosomiasis.The majority are conserved among kinetoplastids but none of them is orthologous to canonical kinetochore proteins, suggesting that kinetoplastids build kinetochores using a distinct set of proteins. By characterizing these unconventional kinetochore proteins in vivo and in vitro, my group aims to reveal the mechanism of chromosome segregation in T. brucei. Obtained insights should lead to a better understanding of the chromosome segregation machinery and may also provide hints into the origin and evolution of the segregation apparatus.

Personal website: https://bungoakiyoshi.com/