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Understanding Early Organogenesis Using a Simplified In Situ Hybridization Protocol in Xenopus
Published on: January 12, 2015
Gap junctional communication in the early Xenopus embryo
Y Landesman1, D A Goodenough, D L Paul
1Department of Neurobiology, Harvard Medical School, Boston, Massachusetts 02115, USA.
The Journal of Cell Biology
|August 23, 2000
Summary
Whole-mount imaging of Xenopus embryos is unreliable for assessing gap junction communication. Rigorous sectioning reveals no dye transfer asymmetry, challenging models of dorso-ventral patterning.
Area of Science:
- Developmental biology
- Cellular biology
- Xenopus embryology
Background:
- Gap junctions facilitate intercellular communication in Xenopus embryos.
- Previous studies suggested asymmetric junctional communication influencing embryonic patterning.
- Lucifer yellow (LY) has been used to investigate this communication.
Purpose of the Study:
- To systematically compare dye transfer of Lucifer yellow (LY) and neurobiotin in Xenopus embryos.
- To rigorously assess the reliability of whole-mount imaging versus sectioned specimens for evaluating gap junctional communication.
- To investigate the role of gap junctional communication in Xenopus dorso-ventral patterning.
Main Methods:
- Coinjection of gap junction-permeable tracers (LY or neurobiotin) with impermeant fluorescent dextrans into Xenopus embryos (16-128 cells).
- Comparison of dye transfer in whole-mount embryos versus fixed and sectioned embryos.
- Assessment of communication patterns after experimental manipulation of embryonic polarity (UV irradiation for ventralization, Xwnt-8 for dorsalization).
Main Results:
- Lucifer yellow (LY) transfer observed in whole-mounts was an artifact of light scattering and pigmentation, not actual intercellular communication.
- No LY transfer was detected in fixed and sectioned embryos.
- Neurobiotin consistently transferred between blastomeres in both dorsal and ventral regions without apparent asymmetry.
- Experimental alterations in embryonic polarity did not affect neurobiotin transfer patterns.
Conclusions:
- Whole-mount imaging is an unreliable method for assessing gap junctional communication in Xenopus embryos.
- Rigorous analysis using sectioned specimens is essential for accurate evaluation of intercellular communication.
- Current models suggesting a role for gap junctional communication in Xenopus dorso-ventral patterning are not supported by these findings.
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