A study led by Toshihiro Kobayashi, a project associate professor at the division of mammalian embryology, The Institute of Medical Science, The University of Tokyo revealed rabbit embryos provide an essential surrogate model for the inaccessible human embryo, as exemplified by observations on the emergence of primordial germ cells (PGCs), precursors of sperm and eggs, in gastrulating rabbit embryos. Published in Cell Reports on October 12th, 2021, the study establishes rabbits as a highly accessible experimental model for other crucial aspects of early human development.
Summary from the paperRabbit embryos develop as bilaminar discs at gastrulation as in humans and most other mammals, whereas rodents develop as egg cylinders. Primordial germ cells (PGCs) appear to originate during gastrulation according to many systematic studies on mammalian embryos.
The research team led by Dr. Kobayashi shows that rabbit PGC (rbPGC) specification occurs at the posterior epiblast at the onset of gastrulation. Using newly derived rabbit pluripotent stem cells, they show robust and rapid induction of rbPGC-like cells in vitro with WNT and BMP morphogens, which reveals SOX17 as the critical regulator of rbPGC fate as in several non-rodent mammals. The team posits that development as a bilaminar disc is a crucial determinant of the PGC regulators, regardless of the highly diverse development of extraembryonic tissues, including the amnion.
They propose that investigations on rabbits with their short gestation, large litters, and a developmental path in which gastrulation precedes implantation can contribute significantly to advances in early mammalian development.
Publication detailsTitle: Tracing the emergence of primordial germ cells from bilaminar disc rabbit embryos and pluripotent stem cells
Journal: Cell Reports
Authors: Toshihiro Kobayashi*, Aracely Castillo-Venzor, Chris A. Penfold, Michael Morgan, Naoaki Mizuno, Walfred W.C. Tang, Yasuyuki Osada, Masao Hirao, Fumika Yoshida, Hideyuki Sato, Hiromitsu Nakauchi, Masumi Hirabayashi*, M. Azim Surani*（*Corresponding author）
Press release in Japanese