Quantitative Dynamics of Chromatin-state Reprogramming for the Mouse Germ-Cell Specification Pathway In Vitro

We re-analyzed gene expression in the primordial germ cell (PGC) specification pathway in vitro, by using previously deposited microarray data. The germ cell lineage produces either spermatozoa or oocytes and, by their fusion, creates zygotes with full developmental potential, thereby perpetuating and diversifying organisms' genetic as well as epigenetic information across generations. In mice, PGCs are specified in the most posterior part of epiblast (monolayer epitherium-like cells, from which the whole embryonic part of conceptus will be derived) around embryonic day (E) 6.25 by a cytokine BMP4. To recaptulate this pathway, an in vitor system was established by Hayashi et al. (2011, 2012): epiblast-like cells (EpiLCs) are induced from embryonic stem cells (ESCs) by cytokine Activin and bFGF, and then PGC-like cells (PGCLCs) are induced from EpiLC by cytokines including BMP4. Similar to the in vivo PGCs, PGCLCs exhibit mesoderm-like profile 2 days after induction (d2 PGCLCs), and then 6 days after induction (d6 PGCLCs), they acquire profiles like PGCs at E9.5 in vivo. We down-loaded data from GEO database (GSM744093, GSM744094, GSM744095, GSM744096, GSM1070847, GSM1070848, GSM744101, GSM744102), and analyzed byu using dChip