Yuki Nakazawa, Ph.D.

Cell biology and morphology

 

Background

I received my Ph.D. (Science) from the University of Tokyo (2008). My dissertation was about how the 9-fold symmetry of the centriole/basal body and the flagellar axoneme is invariably established. Then, I worked as an assistant professor at Kitasato University, subsequently worked as a research associate at the University of Tokyo. Up to this point, my research focus had been on cell biology, especially the cytoskeleton. In 2012, I joined the group working on memory with my husband at the University of California, Davis. After returning to Japan, I restarted my research about centriole assembly as a JSPS research fellow (RPD), a part-time lecturer, and a research associate at Hosei University (2016-2020). At OIST, I’m continuing this project.

Research interests

I’m studying on centriole assembly using green alga Chlamydomonas reinhardtii, a unicellular organism that swims using two flagella (Fig.1).

1) About Chlamydomonas

Chlamydomonas has following advantages: 

  • It is easy to produce mutants because it normally grows in a haploid state.
  • Classical genetic techniques such as a tetrad analysis are available.
  • The databases of its genome, EST, and proteome are available and methods for introducing exogenous genes have been established.
  • it`s centriole/basal body and flagellar axoneme have homologous structures to those of mammalian cells.

 

 

2) About centriole

Centrioles are an important organelle that function as a core of the centrosome and as a base for cilia/flagellar assembly (Fig.2).

This organelle has a cylindrical structure consisting of nine triplet microtubules arranged in rotational symmetry (Fig. 3). Differently from the cytoplasmic microtubule, a dynamic singlet microtubule consisting of 13 protofilaments, the triplet is stable and contains one singlet microtubule (A-tubule) and two additional tubules (B- and C-tubules) consisting of 10 protofilaments. The A- and B-tubules of the triplet are continuous with the outer doublet microtubules of the flagellar axoneme. In other words, the centriole structure defines the 9+2 structure of cilia/flagella axoneme. This 9-fold symmetrical structure is highly conserved among eukaryotes, however, many questions remain about the molecular mechanisms of centriole assembly.

By analyzing centriole/related mutants, my research projects aim to understand the mechanisms of:

  1. Centriole assembly
  2. Triplet microtubule assembly/nucleation
  3. Transition zone (a region between the centriole and the flagellum) assembly and its function.