PUBLICATION

Actin-based endocytosis contributes to zebrafish epiboly

Authors
Cheng, J.C., Miller, A.L., and Webb, S.E.
ID
ZDB-PUB-021017-47
Date
2002
Source
The Journal of general physiology   120(1): 46 (Abstract)
Registered Authors
Miller, Andrew L., Webb, Sarah E.
Keywords
none
MeSH Terms
none
PubMed
none
Abstract
The basic body plan of teleost embryos emerges during the gastrula period when a series of extensive cell movements and rearrangementsepiboly, involution, convergence, and extensionlead to the formation of the three germ layers, the endoderm, mesoderm, and ectoderm as well as the dorsoventral and anterioposterior body axes. Starting toward the end of the blastula period, epiboly consists of the thinning and spreading of both the blastoderm and the yolk syncytial layer (YSL) over the yolk cell toward the vegetal pole until, by the end of the gastrula period, the yolk is completelyencompassed. It has been previously proposed that in Fundulus heteroclitus endocytosis plays a significant role in these morphogenic movements (Trinkaus. 1984. American Zoologist. 24:673688). Here, we present data to suggest that this may also be the case in zebrafish. We report the appearance of a punctate actin band located in the external-YSL at the enveloping layer margin. We propose that this structure may be responsible for the endocytosis of yolk cell membrane and, as in Fundulus, this contributes to the driving force for epiboly. Treatment with cytochalasin B results in the disruption of the punctate band, leading to a slowing down of epiboly compared with controls, a failure of yolk plug occlusion, an elongation of the embryo along itsanimal pole-vegetal pole axis, and eventual lysis of the embryo through the yolk plug. Our new data thus suggest a key role for actin-based endocytosis during the process of epiboly in zebrafish.
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