Title

Expression Pattern Of E-cad, Ocln And Zo-1 In Cleavage-stage Monodelphis Domestica Embryos

Abstract

During blastocyst formation in the laboratory opossum, M. domestica, each blastomere adheres to the zona pellucida, flattens against the zona, and later forms tight junctions with its neighbors. This contrasts greatly with mouse blastocyst formation, wherein cells adhere to each other and later form tight junctions, at no time adhering to the zona. We hypothesized that the spatio-temporal expression of the proteins encoded by E-Cad, Ocln and ZO-1 may explain the difference between eutherian (mouse) and marsupial (opossum) blastocyst formation. Confocal microscopy revealed that E-cadherin is found in both cytoplasm and embryonic coats (zona pellucida, mucoid layer). Its presence in the cytoplasm declined as blastocyst formation became imminent. The tight-junction proteins occludin and zona occludens were expressed similarly in the cytoplasm, although occludin later appeared in the perivitelline space, eventually becoming contained in the blastocoel. Both occludin and zona occludens were detected in zygotic nuclei. Occludin reappeared in larger amounts in cell nuclei during blastocyst formation. The presence of these cell-membrane proteins in nuclei warrants further investigation. Although the antibodies used in this investigation were molecularly similar only E-cadherin, not occludin or zona occludens, was detected in extracellular coats. It is thus unlikely that this E-cadherin expression pattern is artifactual. Rather, its presence in embryonic coats as well as cell surfaces (as occurs in mouse) suggests that it may facilitate blastomere-zona adhesion well in advance of blastomere-blastomere adhesion.

Publisher

Academic Press

Publication Date

8-1-2010

Publication Title

Developmental Biology

Department

Biology

Document Type

Article

DOI

10.1016/j.ydbio.2010.05.114

Keywords

Developmental biology

Language

English

Format

text

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