Biology subjects

Dioguardi, E.

Publications and source records attributed to Dioguardi, E..

3 recordsLinked to original sources

bioRxiv2025

Structural basis of ZP2-targeted immunocontraception

Monoclonal antibody IE-3 prevents mouse fertilization by binding ZP2, a major component of the oocyte-specific zona pellucida (ZP). We show that an IE3-derived single-chain variable fragment (scFV) is sufficient for blocking fertilization in vitro and determine the structural basis of IE-3/ZP2 recognition. The high-affinity of this interaction depends on induced fit of the epitope, offering insights for non-hormonal immunocontraceptive design without off-target effects.

biophysics↗

bioRxiv2023

Architecture of the Vertebrate Egg Coat and Structural Basis of the ZP2 Block to Polyspermy

Post-fertilization cleavage of glycoprotein ZP2, a major subunit of egg zona pellucida (ZP) filaments, is crucial for mammalian reproduction by irreversibly blocking polyspermy. ZP2 processing is thought to inactivate a sperm-binding activity located upstream of the proteins cleavage site; however, its molecular consequences and connection with ZP hardening are unknown. Here we report X-ray crystallographic, cryo-EM and biochemical studies showing that cleavage of ZP2 triggers its oligomerization. Deletion of the ZP-N1 domain that precedes the cleavage site of mouse ZP2 allows it to homodimerize even without processing, and animals homozygous for this variant are subfertile by having a semi-hardened ZP that allows sperm attachment but hinders penetration. Combined with the structure of a native egg coat filament, which reveals the molecular basis of heteromeric ZP subunit interaction, this suggests that oligomerization of cleaved ZP2 cross-links the ZP, rigidifying it and making it physically impenetrable to sperm.

biophysics↗

bioRxiv2019

Molecular basis of egg coat cross-linking sheds light on ZP1-associated female infertility

Interaction between sperm and the egg zona pellucida (ZP) is the first step of mammalian fertilization, and ZP component ZP1 is important for fertility by covalently cross-linking ZP filaments into a matrix. Like ZP4, a structurally-related subunit absent in the mouse, ZP1 is predicted to contain an N-terminal ZP-N domain of unknown function. Characterization of ZP1 proteins carrying mutations from infertile patients suggests that, unlike in the mouse, filament cross-linking by ZP1 is crucial for human ZP assembly. We map the function of ZP1 to its ZP-N1 domain and determine crystal structures of ZP-N1 homodimers from a chicken homolog of ZP1. These reveal that ZP filament cross-linking is highly plastic and can be modulated by ZP1 fucosylation and, potentially, zinc sparks. Moreover, we show that ZP4 ZP-N1 forms non-covalent homodimers in chicken but not human. Together, these data identify human ZP1 cross-links as a promising target for non-hormonal contraception.

biophysics↗