The dorsoventral axis is specified prior to first cleavage in the direct developing sea urchin Heliocidaris erythrogramma.

Published

Journal Article

Previous fate mapping studies as well as the culture of isolated blastomeres have revealed that the dorsoventral axis is specified as early as the 2-cell stage in the embryos of the direct developing echinoid, Heliocidaris erythrogramma. Normally, the first cleavage plane includes the animal-vegetal axis and bisects the embryo between future dorsal and ventral halves. Experiments were performed to establish whether the dorsoventral axis is set up prior to the first cleavage division in H. erythrogramma. Eggs were elongated and fertilized in silicone tubes of a small diameter in order to orient the cleavage spindle and thus the first plane of cell division. Following first cleavage, one of the two resulting blastomeres was then microinjected with a fluorescent cell lineage tracer dye. Fate maps were made after culturing these embryos to larval stages. The results indicate that the first cleavage division can be made to occur at virtually any angle relative to the animal-vegetal and dorsoventral axes. Therefore, the dorsoventral axis is specified prior to first cleavage. We argue that this axis resides in the unfertilized oocyte rather than being set up as a consequence of fertilization.

Full Text

Duke Authors

Cited Authors

  • Henry, JJ; Wray, GA; Raff, RA

Published Date

  • November 1990

Published In

Volume / Issue

  • 110 / 3

Start / End Page

  • 875 - 884

PubMed ID

  • 2088726

Pubmed Central ID

  • 2088726

Electronic International Standard Serial Number (EISSN)

  • 1477-9129

International Standard Serial Number (ISSN)

  • 0950-1991

Language

  • eng