Nakatani, Tsunetoshi

Fertilized eggs are formed through the process of fertilization, in which the egg and sperm—specialized germ cells responsible for transmitting genetic information—fuse to generate a single cell that acquires totipotency. Totipotency is defined as the ability of a single cell to give rise to all cell types and ultimately form a complete organism. In the mouse, our model organism, this totipotent state exists only for a very brief period immediately after fertilization, after which cellular differentiation gradually restricts this developmental potential. Fertilized eggs and germ cells require specialized techniques for handling, and the number of cells that can be obtained is extremely limited. As a result, many of the intracellular processes occurring in these cells have long remained poorly understood. However, recent advances in low-input analytical technologies, multi-omics approaches, and methodological innovations developed by researchers in the field have dramatically improved our ability to investigate these systems. In our laboratory, we utilize these cutting-edge technologies to study fundamental processes in fertilized eggs, including the progression rate of DNA replication forks and the temporal order of genome replication. Currently, our research aims to address the following questions: 1. What molecular mechanisms underlie the acquisition of totipotency in fertilized eggs? 2. What mechanisms generate the unique modes of DNA replication observed in fertilized embryos? 3. What epigenetic manipulations can improve the developmental efficiency of cloned embryos? 4. How is DNA replication regulated during germ cell development? 5. How can cell fate decisions during differentiation and reprogramming be predicted? 6. Which genes are essential for the maintenance of pregnancy? 7. Elucidating Epigenetics and Evolution ================================================= Focusing on DNA methylation, one of the most extensively studied epigenetic regulatory mechanisms, we investigate the evolutionary processes by which organisms acquired genomic imprinting. This project integrates evolutionary biology and molecular biology, representing a highly unique and interdisciplinary research approach.

• Epigenetics
• /Chromatin
• /Histone modification
• /Totipotency
• /Early embryogenesis
• /ゲノムインプリンティング
• /DNA replication