2020年04月17日（金）16:00〜17:00 Understanding the mechanism of chromosome segregation: lessons from diversity

Date/Time

April 17, 2020 (Fri), 16:00-17:00

Place

2F Seminar Room, BioSystems Building

Speaker

Bungo Akiyoshi (University of Oxford)

Title

Understanding the mechanism of chromosome segregation: lessons from diversity

Abstract

Biologists can learn a lot of lessons from exceptions. Although it was widely assumed that the macromolecular protein complex that drives chromosome segregation (called the kinetochore) consists of proteins that are common to all eukaryotes, no canonical kinetochore components have been identified in a group of organisms called kinetoplastids. To reveal how kinetoplastids drive chromosome segregation, we identified 25 kinetochore proteins in Trypanosoma brucei (a kinetoplastid parasite that causes sleeping sickness) and discovered that they constitute kinetochores specific to kinetoplastids. Why do kinetoplastids have unique kinetochores, while all the rest of so-far sequenced eukaryotes have conventional ones? This might reflect the evolutionary history of eukaryotes. Although determining the position of the root of the eukaryotic tree of life remains an unresolved problem, one hypothesis places the root between kinetoplastids and all the rest of eukaryotes, meaning that kinetoplastids might be the earliest-branching eukaryotes. It is therefore possible that kinetoplastids evolved the unique kinetochore system early in the eukaryotic history, whereas other eukaryotes evolved a system utilizing conventional kinetochore proteins. We are currently characterizing the 25 kinetochore proteins in vitro and in vivo to understand how they carry out conserved kinetochore functions, such as binding to DNA and microtubules as well as error correction. By understanding how kinetoplastids segregate their chromosomes, we aim to understand fundamental principles of chromosome segregation machinery.

Host

Tatsuo Fukagawa
Tel: 06-6879-4428
E-mail: tfukagawa@fbs.osaka-u.ac.jp