Ectopic mesodermal expression promoted by the eight-cell stage Bufo arenarum subequatorial cytoplasm |
| |
Authors: | Fernando Campos Casal Mario E Manes |
| |
Institution: | (1) Cátedra de Histología y Embriología, Facultad de Agronomía y Zootecnia, Av. Roca 1900, C.C. 125, Universidad Nacional de Tucumán, 4000, S.M. Tucumán, Argentina E-mail: mmanes@manant.unt.edu.ar Fax: +54-381-4364156/4248025, AR |
| |
Abstract: | Mesodermal determinants were investigated by cytoplasmic transfer and blastomere isolation in the eight-cell stage of Bufo arenarum. Their existence was confirmed by assaying the subequatorial cytoplasm’s ability to respecify the developmental potency of
animal quartets. The gray subequatorial cytoplasm, but not animal cytoplasm, is able to divert the ectodermal fate of animal
quartets to several mesodermal components. The source of the transplanted cytoplasm was important in determining the category
of the resulting structures. Ventral subequatorial cytoplasm from ventrovegetal blastomeres generated ventral derivatives,
namely erythrocytes and mesenchyma. Dorsal subequatorial cytoplasm from dorsovegetal blastomeres produced dorsolateral derivatives,
such as notochord, muscle, nephric tubules, and coelomic epithelium, including mesenchyma. On the other hand, transfer of
vegetal pole cytoplasm to animal quartets resulted in the formation of groups of endoderm-like cells dispersed among epidermal
cells. However, the presence of such cells did not cause any mesodermal induction. The present findings suggest the existence
of cytoplasmic information responsible for mesodermal specification. The alternative hypothesis that animal blastomeres become
mesoderm due to vegetal induction is questioned.
Received: 9 October 1998 / Accepted: 10 March 1999 |
| |
Keywords: | Mesoderm in amphibians Cytoplasmic determinants Localization phenomenon Cytoplasmic transfer Marginal zone cytoplasm |
本文献已被 SpringerLink 等数据库收录! |
|