Egg jelly layers of Xenopus laevis are unique in ultrastructure and sugar distribution

Barry S. Bonnell, Douglas E. Chandler

Research output: Contribution to journalArticlepeer-review

31 Scopus citations


Jelly coats surrounding the eggs of the South African clawed toad, Xenopus laevis, consist of three transparent, gelatinous layers: the innermost layer (J1), the middle layer (J2), and the outer layer (J3). The distribution of N- acetylglucosamine within these jelly coats, as probed with FITC-conjugated wheat germ agglutinin (WGA-FITC), and the matrix ultrastructure of each layer, as visualized in platinum replicas produced by the quick-freeze, deep- etch, and rotary shadowing technique, suggests that each layer has a unique fiber and glycoprotein composition. J1 extends nearly 200 μm from the egg surface and exhibits no WGA-FITC staining. Stereo images of platinum replicas indicates that J1 consists of a tightly knit network of 5-10 nm fibers decorated with 10-20 nm particulate components. In contrast, J2 is a relatively thin layer, extending only 25-40 μm from the outer aspect of J1. When visualized by confocal microscopy, J2 displays a multilayered WGA-FITC staining pattern. The ultrastructure of J2 consists of sheets of fine fibers that run parallel to one another and that can be identified by their ability to bind WGA-colloidal gold. The fibers of each sheet run at an oblique angle to fibers in neighboring layers. J3 extends 100 μm or more from J2. The WGA- FITC staining pattern shows high intensity in its outer region and less intensity in regions closer to J2. Like J1, the J3 ultrastructure consists of a network of 5-10 nm fibers, decorated with 10-20 nm particulate components. The results of these studies add to a growing body of information that suggests the jelly coats surrounding the eggs of many animals consist of a fibrous glycoprotein superstructure that acts as a scaffold to which globular glycoproteins are bound.

Original languageEnglish (US)
Pages (from-to)212-220
Number of pages9
JournalMolecular reproduction and development
Issue number2
StatePublished - Jun 1996


  • Amphibian
  • Egg jelly
  • Extracellular matrix
  • Fertilization
  • Freeze-etching
  • Lectin staining
  • Quick-freezing

ASJC Scopus subject areas

  • Genetics
  • Developmental Biology
  • Cell Biology


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