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Archenteron‐Forming Capacity in Blastomeres Isolated from Eight‐Cell Stage Embryos of the Starfish, Asterina pectinifera
Author(s) -
Maruyama Yoshihiko K.,
Shinoda Masaru
Publication year - 1990
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 - 10.1111/j.1440-169x.1990.00073.x
Subject(s) - blastomere , embryo , starfish , biology , microbiology and biotechnology , polarity in embryogenesis , cleavage (geology) , totipotent , embryogenesis , anatomy , gastrulation , cellular differentiation , genetics , gene , ecology , paleontology , fracture (geology)
Starfish blastomeres are reported to be totipotent up to the 8‐cell stage. We reinvestigated the development of blastomeres of 8‐cell stage embryos with a regular cubic shape consisting of two tiers of 4 blastomeres. On dissociation of the embryo by disrupting the fertilization membrane at the 8‐cell stage, each of the 4 blastomeres of the vegetal hemisphere gave rise to an embryo that gastrulated, whereas blastomeres from the animal hemisphere did not. By injection of a cell lineage tracer into blastomeres of 8‐cell stage embryos, we found that only those of the vegetal hemisphere formed cells constituting the archenteron. Next, we compressed 4‐cell stage embryos along the animal‐vegetal axis so that all the blastomeres in the 8‐cell stage were in a single layer. When these 8 blastomeres were then dissociated, an average of 7 of them developed into gastrulae. By cell lineage analysis, all the blastomeres in single‐layered embryos at the 8‐cell stage were shown to have the capacity to form cells constituting an archenteron. Taken together, these findings indicate that the fate to form the archenteron is specified by a cytoplasmic factor(s) localized at the vegetal hemisphere, and that isolated blastomeres that have inherited this factor develop into gastrulae.