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Activin‐treated ectoderm has complete organizing center activity in Cynops embryos
Author(s) -
Ninomiya Hiromasa,
Ariizumi Takashi,
Asashima Makoto
Publication year - 1998
Publication title -
development, growth and differentiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.864
H-Index - 66
eISSN - 1440-169X
pISSN - 0012-1592
DOI - 10.1046/j.1440-169x.1998.00009.x
Subject(s) - ectoderm , biology , histogenesis , endoderm , mesoderm , anatomy , foregut , embryogenesis , embryo , endocrinology , microbiology and biotechnology , embryonic stem cell , immunohistochemistry , genetics , gene , immunology
The differentiation and organizer activity of newt ectoderm treated with activin A was studied in explantation and transplantation experiments. In the explantation experiments, ectoderm dissected from late morulae–early gastrulae stage embryos treated with a high concentration of activin A (100 ng/mL) formed only yolk‐rich endodermal cells. Mesodermal tissues, such as notochord and muscle, were seldom found in these explants. When they were transplanted into the blastocoele of other early gastrulae, they formed part of the endoderm of the host embryo and induced a secondary axis with only posterior characters (including axial mesoderm and neural tissues). In contrast, whole secondary axes were induced when activin‐treated ectoderm was transplanted into the ventral marginal zone (VMZ) of early blastulae. The transplanted pieces invaginated by themselves and differentiated into foregut structures including pharynx, stomach, and liver. These phenomena were also observed in experiments in which presumptive foregut was used instead of activin‐treated ectoderm. These findings show that activin‐treated ectoderm can act as the complete organizing center in Cynops .