An immunocytochemical localization of the cortical granule lectin in fertilized and unfertilized eggs of xenopus laevis
✍ Scribed by Greve, L. Carl ;Hedrick, Jerry L.
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1978
- Weight
- 476 KB
- Volume
- 1
- Category
- Article
- ISSN
- 0148-7280
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✦ Synopsis
Abstract
At fertilization, the vitelline envelope surrounding the egg of Xenopus laevis is modified by the addition of an electron‐dense component termed the “F layer.” The F layer functions as a block to polyspermy and as a block to the escape of macromolecules from the perivitelline space, thereby causing an osmotically driven envelope elevation. F‐layer formation has been hypothesized to result from interaction between a cortical‐granule lectin, released in the cortical reaction, and a jelly‐coat ligand. Evidence for this hypothesis was sought by determining the location of the cortical‐granule lectin both before and after fertilization, using a specific antibody conjugated to horseradish peroxidase. The cortical‐granule lectin was localized only in the cortical granules of the unfertilized egg and was located predominantly in the perivitelline space and the F layer of a fertilized egg. These observations support the hypothesis that the F layer is formed by a cortical‐granule‐Iectin–jelly layer‐ligand interaction.