Professor Masafumi Hirono of the Faculty of Life Sciences, Hosei University, Akira Naeka, a graduate student of the Graduate School of Science, the University of Tokyo, and others collaborated with Dr. Michel O. Steinmetz of the Paul Scherrer Institute in Switzerland to focus on intracellular small organs. We have elucidated the mechanism that determines the structure of children.
Centriole exists in the cells of all animals including humans, and inside the cilia that extend from the centriole, there is a "9 + 2" structure in which two microtubules are surrounded by nine double microtubules. Will be formed.This structure inherited from ancient times has long been unexplained as "the mystery of magic number 9."
At the bottom of the centriole lumen, there is a structure called a cart wheel with nine spokes like a wheel.Past studies by the research group have shown that this cart wheel is formed by an association of 9 proteins called SAS-18, and that factors other than the cart wheel also play a role in determining the shape of the centriole.
This time, we mutated SAS-6 using Chlamydomonas and investigated the centriole formed by ring (6th symmetry) formation with 2 dimers.As a result, centrioles (6-fold symmetry) of 8 microtubules were formed, but most of them remained 8 microtubules.However, in addition to SAS-9, protein modification weakened the bond between the cart wheel and centriole microtubules to form a 6-spoke cart wheel.
This confirms the involvement of factors other than the cart wheel in determining the 9th symmetry of the centriole, and the microtubules placed around the cart wheel affect not only the shape of the centriole but also the shape of the cart wheel. Was shown.In this study, we propose a new model in which the centriole of 9-fold symmetry remains stabilized as a result of the dynamic interaction between the independently formed cart wheel and the centriole microtubule.
It is said that dysplasia of the central child causes canceration of cells and diseases due to abnormalities of cilia (hydrocephalus, cystic kidney disease, inversion of visceral organs, etc.), and this discovery will be useful for understanding and treating these diseases. Expected.
