Effects of Dithiothreitol on Fertilization and Early Development in Sea Urchin.

Fiche publication


Date publication

décembre 2021

Journal

Cells

Auteurs

Membres identifiés du Cancéropôle Est :
Pr LEHN Jean-Marie


Tous les auteurs :
Limatola N, Chun JT, Cherraben S, Schmitt JL, Lehn JM, Santella L

Résumé

The vitelline layer (VL) of a sea urchin egg is an intricate meshwork of glycoproteins that intimately ensheathes the plasma membrane. During fertilization, the VL plays important roles. Firstly, the receptors for sperm reside on the VL. Secondly, following cortical granule exocytosis, the VL is elevated and transformed into the fertilization envelope (FE), owing to the assembly and crosslinking of the extruded materials. As these two crucial stages involve the VL, its alteration was expected to affect the fertilization process. In the present study, we addressed this question by mildly treating the eggs with a reducing agent, dithiothreitol (DTT). A brief pretreatment with DTT resulted in partial disruption of the VL, as judged by electron microscopy and by a novel fluorescent polyamine probe that selectively labelled the VL. The DTT-pretreated eggs did not elevate the FE but were mostly monospermic at fertilization. These eggs also manifested certain anomalies at fertilization: (i) compromised Ca signaling, (ii) blocked translocation of cortical actin filaments, and (iii) impaired cleavage. Some of these phenotypic changes were reversed by restoring the DTT-exposed eggs in normal seawater prior to fertilization. Our findings suggest that the FE is not the decisive factor preventing polyspermy and that the integrity of the VL is nonetheless crucial to the egg's fertilization response.

Mots clés

BPA-C8-Cy3, Ca2+ signaling, DTT, TCEP, actin, electron microscopy, fertilization, plasticity, sea urchin eggs, vitelline layer

Référence

Cells. 2021 12 17;10(12):