title: Dye-coupling between blastomeres in early embryos ofPatella vulgata (mollusca, gastropoda): Its relevance for cell determination.
abstract: During the early development of the molluscPatella, the dorsoventral axis is established after the fifth cleavage due to direct interaction between the animal micromeres and one of the vegetal macromeres. This vegetal macromere is thereby induced to become the mesentoblast mother cell (3D). In this study we have examined intercellular communication in earlyPatella embryos by monitoring the transfer of the fluorescent dye, Lucifer Yellow, upon iontophoretic injection into blastomeres between the second and sixth cleavage. Up to the fifth cleavage dye transfer is detectable neither inin toto embryos nor in serial sections. Shortly after the fifth cleavage dye-coupling between blastomeres becomes apparent. This occurs approximately 40 min before the interaction between animal micromeres and the future mesentoblast mother cell. Inspection of serially sectioned embryos after dye-iontophoresis in either animal micromeres or in the central macromere 3D showed the absence of direct dye-transfer between these cells at the stage of interaction. The reduced rate of dye-transfer from the 3D macromere to its dorsal neighbour 2d2suggests a bilateral symmetrical transfer pattern, the axis of which corresponds with the dorsoventral axis at the sixth cleavage. Cell deletion experiments demonstrated that the establishment of dye-coupling between the vegetal macromeres occurs independently of the interaction between animal and vegetal blastomeres.
authors.affiliation: Zoological Laboratory, State University of Utrecht, Padualaan 8, 3508 TB, Utrecht, The Netherlands.
authors.forename: Adriaan W C
authors.initials: AW
authors.lastname: Dorresteijn
authors.affiliation: Zoological Laboratory, State University of Utrecht, Padualaan 8, 3508 TB, Utrecht, The Netherlands.
authors.forename: Huibert A
authors.initials: HA
authors.lastname: Wagemaker
authors.affiliation: Hubrecht Laboratory, International Embryological Institute, Uppsalalaan 8, 3584 CT, Utrecht, The Netherlands.
authors.forename: Siegfried W
authors.initials: SW
authors.lastname: de Laat
authors.affiliation: Zoological Laboratory, State University of Utrecht, Padualaan 8, 3508 TB, Utrecht, The Netherlands.
authors.forename: Jo A M
authors.initials: JA
authors.lastname: van den Biggelaar
keywords: Development; Dye-coupling; Gap junctions; Interaction; Mollusca