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Updated: Oct 13, 2025

Primordial Germ Cell Transplantation for CRISPR/Cas9-based Leapfrogging in Xenopus
Published on: February 1, 2018
The X chromosome dosage compensation program during the development of cynomolgus monkeys
Ikuhiro Okamoto1,2, Tomonori Nakamura1,2,3, Kotaro Sasaki2
1Institute for the Advanced Study of Human Biology (ASHBi), Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan.
Abstract:
X chromosome dosage compensation ensures balanced gene dosage between the X chromosome and autosomes and between the sexes, involving divergent mechanisms among mammals. We elucidated a distinct mechanism for X chromosome inactivation (XCI) in cynomolgus monkeys, a model for human development. The trophectoderm and cytotrophoblast acquire XCI around implantation through an active intermediate bearing repressive modifications and compacted structure, whereas the amnion, epiblast, and hypoblast maintain such an intermediate protractedly, attaining XCI by a week after implantation. Males achieve X chromosome up-regulation (XCU) progressively, whereas females show XCU coincidentally with XCI, both establishing the X:autosome dosage compensation by 1 week after implantation. Conversely, primordial germ cells undergo X chromosome reactivation by reversing the XCI pathway early during their development. Our findings establish a foundation for clarifying the dosage compensation mechanisms in primates, including humans.
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