Live Imaging of X-Chromosome Inactivation and Reactivation Kinetics
X-chromosome inactivation (XCI) is an epigenetic phenomenon that equalizes the number of X-linked gene products between male and female eutherian mammals by inactivating one of the two X chromosomes. XCI is essential for female mammalian development, and its failure can lead to embryonic death in mutant mice. The pattern of which X chromosome is inactivated changes dynamically during mouse embryogenesis, depending on developmental stages and tissues. Recent progress in molecular biology, including next-generation sequencing (NGS)-based analyses, enables the analysis of gene expression profiles at a single cell level. Combined with NGS technology, live imaging systems can now be used to track epigenetic events and clarify their casual and spatiotemporal relationships to cell differentiation and embryonic development. Here, I describe a novel live-cell imaging system based on “Momiji” mice for monitoring XCI at the single cell level.
Key wordsLive imaging X-chromosome inactivation Momiji mouse Preimplantation and postimplantation embryos Single cell analysis Enhanced green fluorescent protein
I am grateful to Dr. Kazuo Yamagata at Kindai University for technical and experimental support in live imaging of preimplantation mouse embryos, and Dr. Akira Sato at Carl Zeiss Microscopy Co. Ltd. for technical support and discussion on confocal microscopy observations and quantification. This work was supported by the Japan Science and Technology Agency, Precursory Research for Embryonic Science and Technology (PRESTO) and by Grants-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology (Nos. 23500492, 15H01468, and 26430087) to S.K.