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Published April 1986 | public
Journal Article

Pattern Regulation in the Eyebud of Xenopus Studied with a Vital-Dye Fiber-Tracing Technique

Abstract

Evidence for pattern regulation in the developing Xenopus visual system has previously been obtained after surgical manipulations of the eyebud early in development. In one experimental paradigm, a "compound" eye is produced by combining a nasal (anterior) half-eyebud with normal dorsoventral polarity and a temporal (posterior) half-eyebud with inverted dorsoventral polarity. The adult retinotectal projection from such compound eyes, as assayed by electrophysiological mapping techniques, shows normal dorsoventral polarity in both halves, indicating an apparent reversal in the polarity of the surgically-inverted half. We have utilized a fluorescent vital-dye fiber-tracing technique to investigate the early events in this regulatory process. The results show that the change in dorsoventral polarity is not due to cell movements in the eyebud after surgery. Interestingly, the experiments also demonstrate that the pattern of connections initially formed by the developing eye does not reflect the pattern regulation observed in the adult retinotectal map; instead, the temporal half of the eye projects to the tectum with inverted dorsoventral order. Thus, the regulation observed in the adult does not become evident in the pattern of the projection until after early larval development.

Additional Information

© 1986 Academic Press, Inc. Received March 1, 1985; accepted in revised form November 10, 1985. We thank R. Gimlich and J. Braun for their generous gift of some of the fluorescent dextrans used in this study; V. Bayer for her help with electrophysiological mapping; D. Carhart and D. Valentino for help with the histology; and M. Bronner-Fraser, J. Coulombe, D. Krotoski, and D. Valentino for their careful reading of the manuscript. Preliminary reports of some of this work have appeared (O'Rourke and Fraser, 1984, 1985). This work was supported by grants from the NSF (BNS80-23638, BNS84-06307, and BNS85-11224) and by a McKnight Foundation Scholar's Award.

Additional details

Created:
August 19, 2023
Modified:
October 18, 2023