Many creatures on earth behave with a rhythm of a 24-hour cycle.These behavioral rhythms are created by the clock function of cells throughout the body called the circadian clock.However, there are still many unclear points as to why the cycle length is 24 hours.

　This time, the joint research group has established a new method "high-speed production method for transgenic mice" that efficiently produces genetically modified mice with proteins with variously changed functions.By this method, it became possible to complement the circadian clock function by introducing a gene encoding a protein with variously changed functions into a mouse that has lost the circadian clock function.

　As a result, we found that a specific region of the CRY1 protein, which plays an important role in moving the circadian clock, acts like a timer and determines the cycle length of mice.Since this timer region undergoes a chemical modification (phosphorylation modification) called phosphorylation, which is often used to control protein function in the living body, the phosphorylation modification in the protein skillfully counts the time to make it accurate. It was strongly suggested that there is a possibility of carving a 24-hour cycle.

　In the future, if phosphorylation in this timer region can be controlled with drugs, it is expected that the cycle length of the circadian clock will be efficiently controlled, leading to effective treatment of circadian rhythm sleep disorders and the like.In addition, by using the gene-introduced mouse individual high-speed production method, it becomes possible to produce mice in which cells of the whole body have been genetically modified over a year or more in a few months.Therefore, it is expected that this method will accelerate many studies using genetically modified mice.